2020 商务统计－刘迎春（3321199307）(东北财经大学) 最新满分章节测试答案

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本课程起止时间为:2020-04-26到2020-07-03
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慕课 第六章 Chapter 6 Discrete Probability Distributions 第六单元测试

1、 问题:In an experiment, a random variable represents:
选项：
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.
答案: 【all possible outcomes of an experiment.】

2、 问题:Which of the following statements is true about a probability distribution?
选项：
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.
答案: 【A probability distribution summarizes all possible experimental outcomes and their probability.】

3、 问题:Which of the following is not a characteristic of a binomial distribution?
选项：
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.
答案: 【The outcome of any trial is dependent on the outcomes of previous trials.】

4、 问题:Which probability distribution is applied when the probability of a success is very small?
选项：
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
答案: 【The Poisson probability distribution】

5、 问题:In general, a discrete probability distribution requires that:
选项：
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.
答案: 【the probabilities for all possible outcomes must sum to 1.00.】

6、 问题:In a continuous probability distribution, the random variable:
选项：
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.
答案: 【may be any value within a certain range.】

7、 问题:For a binomial distribution with n = 15, as π changes from 0.05 toward 0.50, the distribution will become:
选项：
A:more positively skewed.
B:more negatively skewed.
C:symmetrical.
D:rectangular.
答案: 【symmetrical.】

8、 问题:For any probability distribution, the expected value is:
选项：
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.
答案: 【equal to the mean of the distribution.】

9、 问题:The expected value of a binomial probability distribution with n = 10 and π = .95 is:
选项：
A:9.5.
B:10.
C:0.95.
D:0.50.
答案: 【9.5.】

10、 问题:The variance of a binomial probability distribution with n = 10 and π = .95 is:
选项：
A:9.50.
B:0.475.
C:100.0.
D:0.9025.
答案: 【0.475.】

慕课 第三章  Chapter 3 Describing Data： Numerical Measures 第三单元测验

1、 问题:A key difference between calculating the sample mean and the population mean is:
选项：
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.
答案: 【we use  and n instead of μ and N.】

2、 问题:Which of the following measures of central location is affected most by extreme values?
选项：
A:Median
B:Mean
C:Mode
D:Variance
答案: 【Mean】

3、 问题:The Empirical Rule states that:
选项：
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.
答案: 【for a bell shaped frequency distribution, approximately 68% of the observations are in the range of plus or minus one standard deviation.】

4、 问题:Which measure of central tendency reports the value that occurs with the highest frequency?
选项：
A:Mean
B:Median
C:Mode
D:Standard deviation
答案: 【Mode】

5、 问题:An example of Chebyshev’s Theorem is:
选项：
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.
答案: 【for any frequency distribution, at least 75% of the observations are in the range of plus or minus two standard deviations from the mean.】

6、 问题: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:
选项：
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.
答案: 【are centered at 10, but sample "A"s data is more concentrated near the mean.】

7、 问题:For a distribution, the mean is 5, the median is 15, and the mode is 20. Based on this information, the distribution is:
选项：
A:positively skewed.
B:negatively skewed.
C:symmetric.
D:bell-shaped.
答案: 【negatively skewed.】

8、 问题:In a positively skewed distribution, which measure of central tendency is the largest?
选项：
A:Mean
B:Median
C:Mode
D:Variance
答案: 【Mean】

9、 问题:Which of the following statistics is a measure of dispersion?
选项：
A:Mean
B:Median
C:Mode
D:Standard deviation
答案: 【Standard deviation】

10、 问题:What is true about the range?
选项：
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.
答案: 【Only two values are used in its calculation.】

慕课 第四章 Chapter 4 Describing Data：  Displaying and Exploring Data 第四单元测验

1、 问题:A dot plot shows:
选项：
A:the general shape of a distribution.
B:the mean, median, and mode.
C:the relationship between two variables.
D:the interquartile range.
答案: 【the general shape of a distribution.】

2、 问题:The test scores for a class of 101 students are computed. What is the location of the test score associated with the third quartile?
选项：
A:75%
B:31
C:50.0
D:76.5
答案: 【76.5】

3、 问题:The test scores for a class of 50 students are computed. What is the location of the test score associated with the second decile?
选项：