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第一章 什么是统计学

第一单元测试

1、the general process of gathering, organizing, summarizing, analyzing, and interpreting data to assist in making effective decisions is called:
    a、statistics.
    b、descriptive statistics.
    c、inferential statistics.
    d、levels of measurement.

2、a sample is:
    a、at least 15 observations.
    b、a group of people.
    c、part of a population.
    d、a set of frequencies.

3、the main purpose of inferential statistics is to:
    a、summarize data in a useful and informative manner.
    b、estimate population characteristics based on a sample information.
    c、determine if the data adequately represents the population.
    d、gather or collect data.

4、to study the characteristics of loan applicants, a random sample of 50 loan applicants is selected and their annual incomes are obtained. which level of measurement is annual income?
    a、nominal
    b、ordinal
    c、interval
    d、ratio

5、the main purpose of descriptive statistics is to:
    a、summarize data in a useful and informative manner.
    b、estimate a population characteristic based on a sample.
    c、determine if the data adequately represents the population.
    d、gather or collect data.

6、a bank asks customers to evaluate the quality of drive-through service as good, average, or poor. which level of measurement is used to measure service quality?
    a、nominal
    b、ordinal
    c、interval
    d、ratio

7、the main purpose of descriptive statistics is to:
    a、summarize data in a useful and informative manner.
    b、estimate a population characteristic based on a sample.
    c、determine if the data adequately represents the population.
    d、gather or collect data.

8、gallup political polls ask people their political party affiliation - democrat, republican or independent. which level of measurement is used to measure party affiliation?
    a、nominal
    b、ordinal
    c、interval
    d、ratio

9、what type of variable is: number of car accidents reported in your city?
    a、attribute
    b、continuous
    c、discrete
    d、qualitative

10、data measured with an ordinal scale:
    a、can be ranked.
    b、have a meaningful value of zero.
    c、have meaningful differences between values.
    d、are quantitative.

第二章 chapter 2 describing data: frequency tables, frequency distributions, and graphic presentation

第二单元测验

1、in a frequency distribution the classes must:
    a、be mutually exclusive.
    b、have a maximum of 10 observations.
    c、have equal frequencies.
    d、be measured on a nominal scale.

2、for a frequency distribution, the class interval is:
    a、the class frequencies divided by two.
    b、the class frequency divided by the number of observations.
    c、the difference between consecutive lower class limits.
    d、the number of observations in the class.

3、for a frequency distribution, a class frequency is:
    a、the number of observations in the class.
    b、the difference between consecutive lower class limits.
    c、limited to a maximum of 10 observations.
    d、the total number of observations in the sample.

4、a research organization is studying the selling price of laptop computers. they selected 25 different computers for the study. to summarize the selling price with a frequency distribution and using the 2k rule, how many classes would you recommend?
    a、10
    b、25
    c、4
    d、5

5、for a frequency distribution, the class midpoint is:
    a、the class interval divided by two and added to the lower limit.
    b、the difference between consecutive lower limits.
    c、the number of observations in the class.
    d、the class frequency divided by the number of observations.

6、which of the following is not a guideline for a frequency distribution?
    a、avoid open-ended classes.
    b、use the 2k rule to determine the number of classes.
    c、make the lower limit of the first class a multiple of the class interval.
    d、each class should have more than 5 observations.

7、to convert a frequency distribution to a relative frequency distribution:
    a、find the difference between consecutive lower class limits.
    b、divide the class frequency by the total number of observations.
    c、divide the lower limit of the first class by the class interval.
    d、multiple the class frequency by 100.

8、a pie chart shows:
    a、the frequency for each class.
    b、the relative frequency for each class.
    c、trends in the data.
    d、the class midpoints.

9、the difference between a histogram and a frequency polygon is:
    a、the frequency polygon is reported as a percent, a histogram does not report percents.
    b、the histogram shows frequencies while a frequency polygon shows cumulative frequencies.
    c、the bars in a histogram and a frequency polygon cannot be adjacent.
    d、open-ended classes can be accommodated with a frequency polygon.

10、in a cumulative frequency polygon:
    a、the class frequencies are converted to percents.
    b、the cumulative frequency for the first class limit is zero.
    c、we add the class frequencies starting with the first class.
    d、all of the above.

第三章 chapter 3 describing data: numerical measures

第三单元测验

1、a key difference between calculating the sample mean and the population mean is:
    a、we use and n instead of μ and n.
    b、we divide the sum of the observations by n - 1 instead of n.
    c、the sample observations are ranked and the middle value is selected as the population mean.
    d、there are no differences.

2、which of the following measures of central location is affected most by extreme values?
    a、median
    b、mean
    c、mode
    d、variance

3、the empirical rule states that:
    a、for a bell shaped frequency distribution, approximately 68% of the observations are in the range of plus or minus one standard deviation.
    b、for a positively skewed frequency distribution, approximately 68% of the observations are in the range of plus or minus one standard deviation.
    c、for a bell shaped frequency distribution, approximately 75% of the observations are in the range of plus or minus one standard deviation.
    d、for a positively skewed frequency distribution, approximately 75% of the observations are in the range of plus or minus one standard deviation.

4、which measure of central tendency reports the value that occurs with the highest frequency?
    a、mean
    b、median
    c、mode
    d、standard deviation

5、an example of chebyshev's theorem is:
    a、for a bell shaped frequency distribution, at least 95% of the observations are in the range of plus or minus two standard deviations from the mean.
    b、for a negatively skewed frequency distribution, at least 95% of the observations are in the range of plus or minus two standard deviations from the mean.
    c、for any frequency distribution, at least 75% of the observations are in the range of plus or minus two standard deviations from the mean.
    d、for a positively skewed frequency distribution, at least 68% of the observations are in the range of plus or minus two standard deviations from the mean.

6、in comparing two different samples of 100 observations, sample "a" has a mean of 10 and a standard deviation of 10. the sample "b" has a mean of 10 and a standard deviation of 50. the two samples are:
    a、exactly the same.
    b、are centered at 10, but sample "a"s data is more concentrated near the mean.
    c、are centered at 10, but sample "b"s data is more concentrated near the mean.
    d、positively skewed.

7、for a distribution, the mean is 5, the median is 15, and the mode is 20. based on this information, the distribution is:
    a、positively skewed.
    b、negatively skewed.
    c、symmetric.
    d、bell-shaped.

8、in a positively skewed distribution, which measure of central tendency is the largest?
    a、mean
    b、median
    c、mode
    d、variance

9、which of the following statistics is a measure of dispersion?
    a、mean
    b、median
    c、mode
    d、standard deviation

10、what is true about the range?
    a、only two values are used in its calculation.
    b、it is in different units than the mean.
    c、it can be used for nominal data.
    d、all values are used in its calculation.

第四章 chapter 4 describing data: displaying and exploring data

第四单元测验

1、a dot plot shows:
    a、the general shape of a distribution.
    b、the mean, median, and mode.
    c、the relationship between two variables.
    d、the interquartile range.

2、the test scores for a class of 101 students are computed. what is the location of the test score associated with the third quartile?
    a、75%
    b、31
    c、50.0
    d、76.5

3、the test scores for a class of 50 students are computed. what is the location of the test score associated with the second decile?
    a、20%
    b、31
    c、10.2
    d、20.5

4、to summarize a data set with a box plot:
    a、two values are required: the 1st quartile and the 3rd quartile.
    b、three values are required: the minimum, median, and maximum.
    c、four values are required: the minimum, 1st quartile, 3rd quartile, and maximum.
    d、five values are required: the minimum, 1st quartile, median, 3rd quartile, and maximum.

5、for a data set, the interquartile range is:
    a、the difference between the minimum and maximum values.
    b、the standard deviation.
    c、the difference between the 1st and 3rd quartiles.
    d、the skewness of a distribution.

6、for any symmetric distribution:
    a、the mean, median, and mode are equal.
    b、compared to the median and mode, the mean is the largest measure of location.
    c、compared to the mean and mode, the median is the largest measure of location.
    d、compared to the mean, median, and mode, the standard deviation is the largest value.

7、for a data set, the coefficient of skewness is -2.73. we conclude that:
    a、the mean is larger than the median.
    b、the median is larger than the mean.
    c、the standard deviation is a less than zero.
    d、something is wrong because the coefficient of skewness cannot be less than -1.00.

8、the purpose of a contingency table is to summarize:
    a、two continuous, ratio variables.
    b、two discrete, ratio variables.
    c、two discrete, nominal or ordinal variables.
    d、two discrete, continuous variables.

9、a scatter diagram:
    a、graphically portrays the relationship between two variables.
    b、uses interval or ratio scale data.
    c、does not allow negative values.
    d、both a and b are correct.

10、contingency tables and scatter diagrams describe:
    a、univariate data.
    b、qualitative data.
    c、bivariate data.
    d、frequency data.

第五章 chapter 5 a survey of probability concepts

第五单元测试

1、which of the following is a correct statement about probability?
    a、probability values range from 0 to 1, inclusive.
    b、probabilities may assume negative values.
    c、probabilities may be greater than 1.
    d、probabilities are limited to one decimal place.

2、probability is defined as:
    a、a number between 0 and 1, inclusive.
    b、the outcome of an experiment.
    c、the likelihood that an event will happen.
    d、an uncertain event.

3、an event is:
    a、a collection of events.
    b、a collection of outcomes from an experiment.
    c、always greater than 1.
    d、measuring or observing an experimental outcome.

4、two events are not independent if:
    a、one event affects the likelihood of another event.
    b、the sum of their probabilities is greater than 1.
    c、we can count the possible outcomes.
    d、one event does not affect the probability of another event.

5、the special rule of addition is used to compute:
    a、the probability of two or more independent events.
    b、the probability of two or more mutually exclusive events.
    c、the probability of two or more collectively exhaustive events.
    d、subjective probabilities.

6、the general rule of addition is used to compute:
    a、the probability of two or more independent events.
    b、the probability of two or more collectively exhaustive events.
    c、the probability of two events, which are not mutually exclusive.
    d、subjective probabilities.

7、the general rule of multiplication is used to compute:
    a、the probability of two or more dependent events.
    b、the probability of two or more independent events.
    c、the probability of two or more mutually exclusive events.
    d、subjective probabilities.

8、the difference between a permutation and a combination is:
    a、in a permutation order is important and in a combination order is not important.
    b、in a permutation order is not important and in a combination it is important.
    c、a combination is based on the classical definition of probability.
    d、a permutation is based on the classical definition of probability.

9、data were collected on 100 students regarding their class and major. the data are summarized in the following contingency table: what is the probability of randomly selecting a sophomore or an undeclared student?
    a、0.19
    b、0.59
    c、0.40
    d、0.29

10、data were collected on 100 students regarding their class and major. the data are summarized in the following contingency table: what is the probability of randomly selecting an undeclared student who is a senior?
    a、0.43
    b、0.30
    c、0.73
    d、0.14

第六章 chapter 6 discrete probability distributions

第六单元测试

1、in an experiment, a random variable represents:
    a、all possible outcomes of an experiment.
    b、the measurement of one experimental outcome.
    c、the probability of an experimental outcome.
    d、the frequency of an outcome.

2、which of the following statements is true about a probability distribution?
    a、a probability distribution summarizes all possible experimental outcomes and their probability.
    b、a probability distribution equals one.
    c、a continuous probability distribution is used to summarize a discrete random variable.
    d、a probability distribution shows the frequency distribution of a random variable.

3、which of the following is not a characteristic of a binomial distribution?
    a、for every trial, the probability of success is the same.
    b、the random variable has only two possible outcomes.
    c、the number of trials is fixed.
    d、the outcome of any trial is dependent on the outcomes of previous trials.

4、which probability distribution is applied when the probability of a success is very small?
    a、the binomial probability distribution
    b、the poisson probability distribution
    c、the empirical probability distribution
    d、the binomial distribution with n = 10 and π = 0.5

5、in general, a discrete probability distribution requires that:
    a、all outcomes must have the same probability of success.
    b、the probabilities for all possible outcomes must sum to 1.00.
    c、the probability of success must be less than 0.1.
    d、the events must be dependent.

6、in a continuous probability distribution, the random variable:
    a、is limited to certain values.
    b、may be any value within a certain range.
    c、may have a probability greater than 1.00.
    d、is discrete.

7、for a binomial distribution with n = 15, as π changes from 0.05 toward 0.50, the distribution will become:
    a、more positively skewed.
    b、more negatively skewed.
    c、symmetrical.
    d、rectangular.

8、for any probability distribution, the expected value is:
    a、equal to the random variable.
    b、equal to the mean of the distribution.
    c、equal to the variance of the distribution.
    d、cannot be greater than 1.

9、the expected value of a binomial probability distribution with n = 10 and π = .95 is:
    a、9.5.
    b、10.
    c、0.95.
    d、0.50.

10、the variance of a binomial probability distribution with n = 10 and π = .95 is:
    a、9.50.
    b、0.475.
    c、100.0.
    d、0.9025.

第七章 chapter 7 continuous probability distributions

第七单元测试

1、a random variable, time to load a delivery truck, is uniformly distributed. the distribution is defined by the:
    a、minimum and maximum times to load a delivery truck.
    b、maximum time to load a delivery truck.
    c、minimum time to load a delivery truck.
    d、standard deviation of the time to lead a delivery truck.

2、a uniform distribution's shape is:
    a、bell shaped.
    b、positively skewed.
    c、negatively skewed.
    d、rectangular.

3、the normal distribution is a _____ distribution.
    a、discrete
    b、continuous
    c、positively skewed
    d、rectangular

4、a normal distribution can be described as a/an ____ distribution.
    a、bell-shaped
    b、summertic
    c、asymptotic
    d、all of the above

5、if a random variable is normally distributed:
    a、the random variable cannot assume negative numbers.
    b、the distribution is defined by the mean and standard deviation of the random variable.
    c、the probability that the random variable is greater than the mean is 0.60.
    d、the probability that the random variable is greater than the mean is 0.60.

6、which of the following statements is correct regarding the standard normal distribution?
    a、it is also called the z distribution.
    b、any normal distribution can be converted to the standard normal distribution.
    c、the mean is 0 and the standard deviation is 1.
    d、all of the above are correct.

7、the area under a standard normal curve between z=0 and z=-1.75 is:
    a、.0401.
    b、.9599.
    c、.4599.
    d、1.4599.

8、the area under a standard normal curve for z values less than 1.75 is:
    a、.0401.
    b、.9599.
    c、.4599
    d、1.4599.

9、in the standard normal distribution, what is the probability of finding a z value between z=-1.25 and z=-1.00?
    a、0.3944
    b、0.3413
    c、0.7357
    d、0.0531

10、in the standard normal distribution, what is the z-statistic for the 80th percentile?
    a、0.8400
    b、0.2881
    c、0.2000
    d、0.8000

第八章 chapter 8 sampling methods and the central limit theorem

第八单元测试

1、a simple random sample assures that:
    a、all items in a population have an equal probability of selection.
    b、the sample will be at least 30 observations.
    c、the sample size will be equal to the population size, n.
    d、the sample will be biased.

2、sampling is often preferred to surveying a population because:
    a、surveying a population can be very expensive.
    b、it can be physically impossible to find all the items in the population.
    c、sample estimates can be very accurate.
    d、all of the above are reasons for sampling.

3、which of the following is a method of probability sampling?
    a、simple random sampling
    b、systematic sampling
    c、stratified sampling
    d、all of the above are methods of probability sampling.

4、in a simple random sample:
    a、every kth item is selected to be in the sample.
    b、every item has a chance to be in the sample.
    c、every item has the same chance to be in the sample.
    d、only 10 items are selected.

5、suppose a population consisted of 20 items. how many different samples of n = 3 are possible?
    a、6840
    b、1140
    c、20
    d、120

6、the difference between the sample mean and the population mean is called the:
    a、population deviation.
    b、population standard deviation.
    c、standard error of the mean.
    d、sampling error.

7、for the sampling distribution of sample means, what is the relationship between the population mean and the mean of all possible sample means of size 25?
    a、they are equal.
    b、they are not equal.
    c、they are different by one standard error of the mean.
    d、they are both normally distributed.

8、when comparing the variances of a population distribution and a sampling distribution of means from the population the:
    a、variances are equal.
    b、population variance is smaller than the sampling distribution variance.
    c、population variance is larger than the sampling distribution variance.
    d、variances have the same degrees of freedom.

9、the standard error of the mean is:
    a、the standard deviation of the sampling distribution of sample means.
    b、always normally distributed.
    c、sometimes less than 0.
    d、the variance squared.

10、a population distribution is normal with a mean of 18 and standard deviation of 4. a sample of 16 observations is selected and a sample mean computed. what is the probability that the sample mean is more than 18?
    a、0.5
    b、1.0
    c、0.0
    d、18

第九章 chapter 9 estimation and confidence intervals

第九单元测验

1、when estimating population parameters, a point estimate is:
    a、a range of possible values for a population parameter.
    b、always equal to a population value.
    c、a statistic that estimates a population parameter.
    d、the population mean.

2、a characteristic of all confidence intervals is that:
    a、a confidence interval always includes the population parameter.
    b、a confidence interval always increases in width as the sample size is increased.
    c、a confidence interval cannot include a value of 0.
    d、a confidence interval always increases in width as the level of confidence increases.

3、if we wish to decrease the width (increase the precision) of a confidence interval, we would:
    a、increase the size of the sample.
    b、reduce the size of the population.
    c、raise the level of confidence.
    d、compute the mean.

4、we wish to develop a confidence interval for the population mean. the population standard deviation is known. we have a sample of 40 observations. we decide to use the 92 percent level of confidence. the appropriate value of z is:
    a、1.96.
    b、1.65.
    c、2.58.
    d、1.75.

5、which of the following statements is a characteristic of the t distribution?
    a、it is a continuous distribution.
    b、it has a mean of 0.
    c、it is symmetrical.
    d、all of the above.

6、we wish to develop a confidence interval for the population mean. the population follows the normal distribution, the standard deviation of the population is 3, and we have a sample of 10 observations. we decide to use the 90 percent level of confidence. the appropriate statistic for the level of confidence is:
    a、z = 1.645.
    b、z = 1.960.
    c、t = 1.833.
    d、t = 2.262.

7、the fraction of a sample possessing a certain trait is called a:
    a、population.
    b、mean.
    c、confidence interval.
    d、proportion.

8、to develop a confidence interval for a proportion:
    a、we approximate the binomial distribution with a normal distribution.
    b、the sample size should be at least 100.
    c、p should be less than .05.
    d、we use the t statistic.

9、we wish to develop a confidence interval for the population mean. the population follows the normal distribution and the population standard deviation is 3. we collect a random sample of 10 observations. we decide to use the 90 percent level of confidence. the margin of error for the confidence interval is:
    a、± 1.645.
    b、± 1.565.
    c、± 2.262.
    d、± 2.146.

10、we wish to develop a confidence interval for the population mean. the population follows the normal distribution. we collect a random sample of 10 observations and the sample standard deviation is 3. we decide to use the 95 percent level of confidence. the margin of error for the confidence interval is:
    a、± 1.859.
    b、± 1.960.
    c、± 2.262.
    d、± 2.146.

第十章 chapter 10 one sample tests of hypothesis

第十单元测验

1、for a null hypothesis statement, it always includes:
    a、a hypothesized value for the sample statistic.
    b、a statement of equality: (=), (≤) or (≥).
    c、a statement of less than: (<).
    d、a statement of greater than: (>).

2、which of the following statements is true about the alternate hypothesis?
    a、it is accepted if the null hypothesis is rejected.
    b、it will always contain an equal sign.
    c、it is rejected if the null hypothesis is true.
    d、it is accepted if the null hypothesis is accepted.

3、which of the following statements is true about the level of significance?
    a、it is a probability.
    b、it can be any value between 0 and 1.
    c、it is the likelihood of rejecting the null hypothesis when it is true.
    d、all of the above.

4、a type i error is:
    a、calculated from sample information.
    b、a probability determined from the test statistic.
    c、the probability of rejecting the null hypothesis when it is true.
    d、the probability of accepting the null hypothesis when it is false.

5、when testing a null hypothesis, a critical value is:
    a、calculated from sample information.
    b、always positive.
    c、the point that divides the acceptance region from the rejection region.
    d、a probability determined from the test statistic.

6、in a one-tailed hypothesis test:
    a、the rejection region is in only one of the tails of a distribution.
    b、the rejection region is split between the tails of a distribution.
    c、the area of the rejection region equals the p-value.
    d、the area of the rejection region is twice the value of the p-value.

7、to use a z statistic in a one-sample hypothesis test of a mean, we need to know:
    a、the population mean.
    b、the population standard deviation.
    c、the degrees of freedom.
    d、the margin of error.

8、a p-value is equal to the:
    a、population proportion.
    b、significance level.
    c、fraction of the population that has a particular characteristic.
    d、probability of finding a value of the test statistic that is equal or more extreme (greater than or less than) than the value of the test statistic assuming the null hypothesis is true.

9、a type ii error occurs when we:
    a、accept the null hypothesis when it is false.
    b、reject the alternate hypothesis when it is true.
    c、reject the null hypothesis when it is false.
    d、accept the null hypothesis when it is true.

10、which of the following statements are correct when deciding whether to use the z or the t distribution?
    a、use the z distribution in a test of proportions when nπ and n(1 - π) are greater than or equal to 5.
    b、use the z distribution when we have a normal population and we know the population standard deviation.
    c、use t when the population is normal and the population standard deviation is not known.
    d、all of the above statements are correct.

第十一章 chapter 11 two-sample tests of hypothesis

第十一单元测验

1、in a hypothesis test comparing two population means, the "=" sign always appears in the:
    a、null hypothesis.
    b、alternate hypothesis.
    c、upper tail of the test statistic.
    d、lower tail of the test statistic.

2、in a hypothesis test comparing two population means, we use the z distribution when:
    a、the two population standard deviations are equal.
    b、both populations have at least 4000 observations.
    c、both population standard deviations are known.
    d、nπ and n(1-π) are both greater than 5.

3、for the hypothesis, h0: µ1 ≤ µ2, a random sample of 10 observations is selected from the first normal population and 8 from the second normal population. what is the number of degrees of freedom?
    a、18
    b、17
    c、16
    d、9

4、for the hypothesis, h0: µ1 ≤ µ2, (.01 significance level), a random sample of 10 observations is selected from the first normal population and 8 from the second normal population. population standard deviations are unknown. what is (are) the critical value(s)?
    a、2.583
    b、-2.921, 2.921
    c、-2.583, 2.583
    d、-2.583

5、when testing a hypothesis about the means for two independent populations (population standard deviations unknown), what should be true?
    a、nπ and n(1-π) are both greater than 5.
    b、both populations are normally distributed.
    c、the samples sizes selected from each population must be equal.
    d、the observations are matched or paired.

6、to conduct a test of means for two independent populations, which of the following is required?
    a、a z-statistic is used to test the hypothesis.
    b、the population standard deviations must be equal.
    c、nπ and n (1 - π) must be 5 or greater.
    d、a one-tailed hypothesis test.

7、another way to state the null hypothesis: h0: µ1 = µ2, is:
    a、h0: µ1 ≤ µ2
    b、h0: µ1 - µ2 = 0
    c、h0: µ1 ≥ µ2
    d、h0: µ1 - µ2 ≠ 0

8、to conduct a test of hypothesis for dependent populations, we assume that:
    a、the distribution of the difference between the sampled paired observations follows the normal distribution.
    b、both samples are at least 30.
    c、the samples are unrelated.
    d、nπ and n(1-π) are both greater than 5.

9、when conducting a test of hypothesis for dependent samples:
    a、the sample size should be at least 30 pairs of observations.
    b、the significance level is more than .05.
    c、the p-value is more than .10.
    d、differences between each matched pair of observations are computed.

10、which of the following is not necessary to determine a p-value?
    a、knowledge of whether the test is one-tailed or two-tailed
    b、the value of the test statistic
    c、the level of significance
    d、sample size

第十二章 chapter 12 analysis of variance

第十二单元测验

1、a f-statistic is used to test the hypothesis that:
    a、mse equals 0.
    b、two population variances are equal.
    c、a z-statistic is greater than 0.
    d、a z statistic less than a t statistic.

2、the shape of a f-distribution is:
    a、positively skewed.
    b、symmetric.
    c、negatively skewed.
    d、uniform.

3、a one-way anova is a statistical technique used to test a null hypothesis of equal population:
    a、variances.
    b、proportions.
    c、means.
    d、skewness.

4、in a one-way anova, the f test statistic is the ratio of the:
    a、treatment and error mean squares.
    b、total and error mean squares.
    c、total and treatment squares.
    d、two treatment variances.

5、which of the following is a characteristic of the f distribution?
    a、it is a discrete distribution.
    b、it cannot be positive.
    c、it is based on the ratio of two population variances.
    d、it is the ratio of two population means.

6、in an anova table, the term "treatment" refers to:
    a、a source of variation.
    b、the numerator degrees of freedom.
    c、the variation within the cells.
    d、error variation.

7、suppose we want to test the effect of three treatments. we randomly assign 6 observations to each treatment. for an anova, the treatment and error degrees of freedom are:
    a、3 and 6.
    b、3 and 18.
    c、2 and 15.
    d、2 and 18.

8、the term mse is:
    a、the treatment mean square.
    b、the error mean square.
    c、an estimate of the common sample variance.
    d、an estimate of the population mean.

9、anova requires that the:
    a、populations are normally distributed.
    b、populations have equal means.
    c、samples are dependent.
    d、population variances are not equal.

10、when will the computed value of f be negative?
    a、when there is no difference in the treatment means.
    b、when there is no difference in the block means.
    c、when the ss total is larger than sst.
    d、f cannot be negative.

第十三章 chapter 13 linear regression and correlation

第十三单元测试

1、in a scatter diagram:
    a、the dependent variable is scaled along the horizontal axis.
    b、the independent variable is scaled along the vertical axis.
    c、the graph shows the relationship between two variables.
    d、the probabilities are plotted.

2、a correlation measures the:
    a、relationship between several independent variables.
    b、strength of the association between two variables.
    c、strength of the association between two variances.
    d、strength of the association between two means.

3、the sample correlation coefficient:
    a、has the same sign as the slope of the regression equation.
    b、can range from -1.00 up to 10.00
    c、is also called student's t.
    d、has "n" degrees of freedom.

4、the coefficient of determination is:
    a、the square root of the correlation coefficient.
    b、between -1.00 and 1.00.
    c、equal to (1 - (sse/ ss total)).
    d、the treatment mean square plus the error mean square.

5、suppose we developed the following least squares regression equation: . what can we conclude?
    a、the dependent variable increases 3.5 for each unit increase in x.
    b、the equation crosses the y-axis at 2.1.
    c、if x = 5, then is 14.
    d、there is a significant positive relationship between the dependent and independent variables.

6、the standard error of estimate is based on:
    a、squared deviations from the regression line.
    b、negative values.
    c、squared units of the independent variable.
    d、the regression mean square error.

7、which of the following is not a necessary condition for regression analysis?
    a、the standard deviation of each of the conditional distributions must be the same.
    b、the y values are independent.
    c、for each x value, there is a group of y values and these y values are normally distributed.
    d、the slope of the regression line is positive (increasing).

8、which of the following statistics is not based on squared deviations from the regression line?
    a、the correlation coefficient
    b、the coefficient of determination
    c、the residuals
    d、the standard error of estimate

9、the term (ssr/ss total) is also called the:
    a、sum of squares due to regression.
    b、coefficient of determination.
    c、standard error of estimate.
    d、correlation coefficient.

10、if the coefficient of determination is 95%, then:
    a、95% of the variation in the dependent variable is explained by the independent variable.
    b、95% of the variation in the independent variable is explained by the dependent variable.
    c、the regression equation is 95% correct.
    d、95% of the time, the confidence interval is a good estimate.

第十四章 chapter 14 multiple linear regression and correlation analysis

第十四单元测试

1、in a multiple regression equation, there are:
    a、two or more dependent variables.
    b、two or more independent variables.
    c、two or more intercept values.
    d、multiple coefficients of determination.

2、in regression analysis, a dummy variable or indicator variable:
    a、may assume only a value of 0 or 1.
    b、is another term for the dependent variable.
    c、is found by (y – ŷ).
    d、is equal to ŷ.

3、the multiple standard error of estimate is:
    a、found by taking the square root of ssr/ss total.
    b、negative when one of the net regression coefficients is 0.
    c、based on the term, (y – ŷ) 2.
    d、the error of estimating the regression coefficients.

4、in the anova table for a multiple regression analysis, the value of k is the:
    a、regression sum of squares.
    b、total number of observations.
    c、total degrees of freedom.
    d、regression degrees of freedom.

5、a correlation matrix shows the following:
    a、all simple correlation coefficients.
    b、all possible net regression coefficients.
    c、only positive correlation coefficients.
    d、the multiple regression equation.

6、which of the following statements is true for a multiple regression equation?
    a、there is only one dependent variable.
    b、the term must be at least .50.
    c、all the regression coefficients must be between -1.00 and 1.00.
    d、there is only one (y – ŷ).

7、multicollinearity occurs when the following condition exists:
    a、the residuals are correlated.
    b、time is involved in the analysis.
    c、the independent variables are correlated.
    d、the residuals are not constant for all ŷ values.

8、for a multiple regression analysis, the global hypothesis test determines:
    a、which regression coefficients do not equal 0.
    b、whether any of the regression coefficients differ from 0.
    c、whether any of the correlation coefficients differ from 0.
    d、whether the intercept differs from 0.

9、to test the significance of individual regression coefficients:
    a、we use a t statistic.
    b、we test for differences between each pair of regression coefficients.
    c、we usually delete the variables where the null hypothesis is rejected.
    d、regression coefficients with a negative coefficient are deleted from the equation.

10、stepwise regression is a method to:
    a、eliminate insignificant variables from a multiple regression equation.
    b、select the best regression equation with a single independent variable.
    c、increase the total sum of squares.
    d、select independent variables to include in a multiple regression equation that increase the multiple coefficient of determination the most.

第十五章 chapter 15 chi-square applications

第十五单元测试

1、to conduct a nonparametric hypothesis test:
    a、to conduct a nonparametric hypothesis test:
    b、the standard deviation must be known.
    c、it is not necessary to make any assumption about the shape of the population.
    d、the data must be at least interval scale.

2、which of the following statements is true of the χ2 distribution?
    a、it is a continuous probability distribution.
    b、the χ2 statistic is always greater than or equal to zero.
    c、it is negatively skewed.
    d、it approaches a uniform distribution as the degrees of freedom increase.

3、in a goodness-of-fit test where the sample of 200 observations are distributed among 5 categories, what is the critical value of χ2 for a significance level of 0.05?
    a、9.488
    b、11.070
    c、43.773
    d、195.000

4、a goodness-of-fit test requires that:
    a、all the cell frequencies must be the same.
    b、there must be at least 30 observations.
    c、forty percent of the cells must contain at least 10 observations.
    d、expected cell frequencies should be 5 or more.

5、which statement best describes a contingency table?
    a、a contingency table must have equal numbers of rows and columns.
    b、a contingency table summarizes one variable that is classified according to two criteria.
    c、a contingency table requires at least 10 observations in each cell.
    d、a contingency table summarizes the frequencies of two variables.

6、in a contingency table a sample of 400 people is classified by gender and four hair colors (blond, brown, black, and red). how many degrees of freedom are there?
    a、1
    b、3
    c、8
    d、399

7、which statement is true for a χ2 goodness-of-fit test?
    a、there is only one degree of freedom.
    b、the rejection region is in the upper right tail.
    c、the scale of measurement is interval.
    d、we must assume a normal population.

8、to find the expected frequencies in a contingency table, do the following:
    a、compute the square root of the degrees of freedom.
    b、multiple the row total by the column total and divide the result by the grand total.
    c、subtract one from the total number of observations.
    d、divide the total number of observations by the number of cells in the table.

9、a researcher collects a random sample of 120 observations to study a demographic variable that is classified into 6 categories. we wish to investigate whether the number of observations is the same in each of the categories for the population. which test is this?
    a、this is a χ2 goodness-of-fit test with 5 degrees of freedom.
    b、this is a χ2 goodness-of-fit test with 97 degrees of freedom.
    c、this is a χ2 goodness-of-fit test with 3 degrees of freedom.
    d、this is a student's t goodness-of-fit test with 5 degrees of freedom.

10、under what conditions could the χ2 distribution assume negative values?
    a、when the sample size is small
    b、when the cell frequencies are all equal
    c、when the degrees of freedom is 1
    d、never

期末考试 final examination

期末考试

1、what is the level of measurement of dress size?
    a、nominal
    b、ordinal
    c、interval
    d、ratio

2、a uniform distribution is defined over the interval from 2 to 8, the probability of a value more than 4 is
    a、0.25
    b、0.33
    c、0.5
    d、0.67

3、a data set consists of 145 observations that range from 60 to 460, the number of classes should be ( ) for a frequency distribution.
    a、6
    b、7
    c、8
    d、9

4、data were collected on 100 students regarding their class and major. the data are summarized in the following contingency table: the probability of randomly selecting a sophomore given he or she is an undeclared student is ( )
    a、19/100
    b、19/29
    c、19/30
    d、30/100

5、a machine shop has 100 drill presses and other machines in constant use. the probability that a machine will become inoperative during a given day is 0.002. during some days, no machines are inoperative, but during some days, one, two, three, or more are broken down. what is the probability that fewer than two machines will be inoperative during a particular day?
    a、0.0200
    b、0.1637
    c、0.8187
    d、0.9824

6、there are five balls with different colors which will be arranged in front of a house. how many different ways can the balls be arranged?
    a、120
    b、25
    c、3125
    d、1

7、the jersey numbers on baseball uniforms is an example of the _______ level of measurement.
    a、nominal
    b、ordinal
    c、ratio
    d、interval

8、which of the following is most affected by an outlier (extreme value)?
    a、mean
    b、median
    c、mode
    d、none of the above

9、fred exercises regularly. his fitness log for the last 12 months shows that he jogged 30% of the days, rode his bike 20% of the days, and did both on 12% of the days. what is the probability that fred would do none of these two types of exercises on any given day?
    a、50%
    b、38%
    c、88%
    d、62%

10、a major credit card company has determined that customers charge between $120 and $150 per week. if the weekly amount charged is uniformly distributed, the standard deviation of the charge would be ______ $.
    a、8.66
    b、75
    c、135
    d、270

11、the incomes of 50 loan applicants are obtained. which level of measurement is income?
    a、nominal
    b、ordinal
    c、interval
    d、ratio

12、the weekly sales from a sample of 10 computer stores yielded a mean of $25,900, a median of $25,000, and a mode of $24,500. given this, the shape of the distribution would be _________.
    a、positively skewed
    b、negatively skewed
    c、symmetric
    d、uncertain

13、according to chebyshev's theorem, at least what percent of the observations lie within plus and minus 1.75 standard deviations of the mean?
    a、56%
    b、95%
    c、67%
    d、100%

14、a study of 200 computer service firms revealed these incomes after taxes ( ) what is the probability that a particular firm selected has $1 million or more in income after taxes?
    a、0.00
    b、0.25
    c、0.49
    d、0.51

15、in a management trainee program, 80% of the trainees are female, 20% male. a total of 90% of the females attended college, while 78% of the males attended college. a management trainee is selected at random. what is the probability that the person selected is a female who did not attend college?
    a、0.20
    b、0.08
    c、0.25
    d、0.80

16、a bank asks customers to evaluate the quality of drive-through service as good, average, or poor. which level of measurement is used to measure service quality?
    a、nominal
    b、ordinal
    c、interval
    d、ratio

17、which of the following measures of central location is affected most by extreme values?
    a、median
    b、mean
    c、mode
    d、variance

18、an example of chebyshev's theorem is__________
    a、for a bell shaped frequency distribution, at least 95% of the observations are in the range of plus or minus two standard deviations from the mean.
    b、for a negatively skewed frequency distribution, at least 95% of the observations are in the range of plus or minus two standard deviations from the mean.
    c、for any frequency distribution, at least 75% of the observations are in the range of plus or minus two standard deviations from the mean.
    d、for a positively skewed frequency distribution, at least 68% of the observations are in the range of plus or minus two standard deviations from the mean.

19、a characteristic of all confidence intervals is that_____
    a、a confidence interval always includes the population parameter.
    b、a confidence interval always increases in width as the sample size is increased.
    c、a confidence interval cannot include a value of 0.
    d、a confidence interval always increases in width as the level of confidence

20、the mean and variance are equal for________
    a、all probability distributions.
    b、the binomial probability distribution
    c、the poisson probability distribution
    d、the empirical probability distribution

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