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True / False Questions 1. An independent samples experiment is an experiment in which there is no relationship
between the measurements in the different samples.
True False 1818 Chapter 01  An Introduction to Business Statistics 2. When testing the difference between two proportions selected from populations with large
independent samples, the Z test statistic is used.
True False 3. In forming a confidence interval for
, only two assumptions are required:
independent samples and sample sizes of at least 30.
True False 4. In testing the equality of population variances, two assumptions are required: independent
samples and normally distributed populations.
True False 5. In an experiment involving matched pairs, a sample of 12 pairs of observations is collected.
The degree of freedom for the t statistic is 10.
True False 6. When comparing two independent population means, if n1 = 13 and n2 = 10, degrees of
freedom for the t statistic is 22.
True False 1819 Chapter 01  An Introduction to Business Statistics 7. When comparing the variances of two normally distributed populations using independent
random samples, if
True False , the calculated value of F will always be equal to one. 8. In testing the difference between two population variances, it is a common practice to
compute the F statistic so that its value is always greater than or equal to one.
True False 9. The F statistic can assume either a positive or a negative value.
True False 10. There are two types of machines called type A and type B. Both type A and type B can be
used to produce a certain product. The production manager wants to compare efficiency of the
two machines. He assigns each of the fifteen workers to both types of machines to compare
the hourly production rate of the 15 workers. In other words, each worker operates machine A
and machine B for one hour each. These two samples are independent.
True False 11. In testing the difference between two means from two independent populations, the
sample sizes do not have to be equal to be able to use the Z statistic.
True False 12. In testing the difference between the means of two normally distributed populations using
large independent random samples, the sample sizes from the two populations must be equal
in order to use a Z statistic.
True False 1820 Chapter 01  An Introduction to Business Statistics 13. In testing the difference between the means of two normally distributed populations using
large independent random samples, the alternative hypothesis indicates no differences
between the two specified means.
True False 14. In testing the difference between the means of two normally distributed populations using
large independent random samples, we can only use a twosided test.
True False 15. In testing the difference between the means of two independent populations, if neither
population is normally distributed, then the sampling distribution of the difference in means
will be approximately normal provided that the sum of the sample sizes obtained from the two
populations are at least 30.
True False 16. When comparing two population means based on independent random samples, the
pooled estimate of the variance is used if both population standard deviations are known.
True False 17. Assume that we are constructing confidence interval for the difference in the means of
two populations based on independent random samples. If both sample sizes
and the distribution of both populations are highly skewed, then a confidence interval for the
difference in the means can be constructed using the t test statistic.
True False 18. If the limits of the confidence interval of the difference between the means of two
normally distributed populations were 8.5 and 11.5 at the 95% confidence level, then we can
conclude that we are 95% certain that there is a significant difference between the two
population means.
True False 1821 Chapter 01  An Introduction to Business Statistics 19. If the limits of the confidence interval of the difference between the means of two
normally distributed populations were from 2.6 and 1.4 at the 95% confidence level, then we
can conclude that we are 95% certain that there is a significant difference between the two
population means.
True False 20. When we are testing a hypothesis about the difference in two population proportions
based on large independent samples, we compute a combined (pooled) proportion from the
two samples if we assume that there is no difference between the two proportions in our null
hypothesis.
True False Multiple Choice Questions 21. In testing for the equality of variances from two independent populations, if the null
hypothesis is false, the test could result in:
A. A Type I error.
B. Either a Type I error or a Type II error.
C. Neither a Type I error or a Type II error.
D. A Type II error.
E. Both a Type I error and a Type II error. 22. In testing for the equality of means from two independent populations, if the null
hypothesis is rejected, the test could result in:
A. A Type I error.
B. Either a Type I error or a Type II error.
C. Neither a Type I error or a Type II error.
D. A Type II...
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 Winter '14

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