Statistical Analysis II

The __________ test is useful for before/after experiments.

	A. goodness-of-fit
	B. sign
	C. median
	D. chi-square

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The __________ test is useful for drawing conclusions about data using nominal level of measurement.

	A. goodness-of-fit
	B. sign
	C. median
	D. chi-square

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In an experiment, a sample size of 10 is drawn, and a hypothesis test is set up to determine: H₀ : p = 0.50; H₁:p < or = 0.50; for a significance level of .10, the decision rule is as follows:

	A. Reject H0 if the number of successes is 2 or less.
	B. Reject H0 if the number of successes is 8 or more.
	C. Reject H0 if the number of successes is three or less.
	D. Reject H0 if the number of successes is less than 2 or more than 8.

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For a “before and after” test, 16 of a sample of 25 people improved their scores on a test after receiving computer-based instruction. For H₀ : p = 0.50; H₁:p is not equal to 0.50; and a significance level of .05:

	A. z = 1.2, fail to reject the null hypothesis.
	B. z = 1.4, reject the null hypothesis.
	C. z = 1.4, fail to reject the null hypothesis.
	D. z = 1.64, reject the null hypothesis.

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A sample group was surveyed to determine which of two brands of soap was preferred. H₀ :p = 0.50; H₁: p is not equal to 0.50. Thirty-eight of 60 people indicated a preference. At the .05 level of significance, we can conclude that:

	A. z = 0.75, fail to reject H0.
	B. z = 1.94, fail to reject H0.
	C. z = 1.94, reject H0.
	D. z = 2.19, reject H0.

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The performance of students on a test resulted in a mean score of 25. A new test is instituted and the instructor believes the mean score is now lower. A random sample of 64 students resulted in 40 scores below 25. At a significance level of α = .05:

	A. H0 : p = 0.50; H1:p < 0.50.
	B. H0 : p = 0.50; H1:p > 0.50.
	C. H0 : p = 25; H1:p > 25.
	D. H0 : p = 25; H1:p < 25.

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From the information presented in question #6:

	A. z = 3.75, we can reject the null hypothesis.
	B. z = 1.875, we fail to reject the null hypothesis.
	C. z = -1.625, we fail to reject the null hypothesis.
	D. z = -1.875, we can reject the null hypothesis.

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A golf club manufacturer claims that the median length of a drive using its driver is 250 yards. A consumer group disputes the claim, indicating that the median will be considerably less. A sample of 500 drives is measured; of these 220 were above 250 yards, and none was exactly 250 yards. The null and alternate hypotheses are:

	A. Ho: 0 = 250; H1: 0 < 250.
	B. Ho: median = 250; H1: median > 250.
	C. Ho: 0 > 250; H1: 0 < 250.
	D. Ho: median = 250; H1: median < 250.

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From the information presented in question #8, using a level of significance = .05:

	A. z = -1.74; we should fail to reject the null hypothesis.
	B. z = 2.64; we should fail to reject the null hypothesis.
	C. z = -2.72; we should fail to reject the null hypothesis.
	D. z = -3.17; we should reject the null hypothesis.

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The Wilcoxon rank-sum test:

	A. is a nonparametric test for which the assumption of normality is not required.
	B. is used to determine if two independent samples came from equal populations.
	C. requires that the two populations under consideration have equal variances.
	D. Both A and B

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A nonparametric test which can evaluate ordinal-scale data of a non-normal population is called the:

	A. Wilcoxon signed rank test.
	B. Kruskal-Wallis test.
	C. sign test.
	D. median test.

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A researcher wishes to test the differences between pairs of observations with a non-normal distribution. She should apply the:

	A. Wilcoxon signed rank test.
	B. Kruskal-Wallis test.
	C. Wilcoxon rank-sum test.
	D. t test.

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The data below indicate the rankings of a set of employees according to class theory and on-the-job practice evaluations:

Theory	1	7	2	10	4	8	5	3	6	9
Practice	2	8	1	7	3	9	6	5	4	10

What is the Spearman correlation of coefficient for the data?

	A. -0.0606
	B. 0.1454
	C. 0.606
	D. 0.8545

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For the value of rs determined, a test of significance indicates that:

	A. t = -0.45, a weak negative relationship between the two variables.
	B. t = – 0.06, a strong negative relationship between the variables.
	C. t = 0.45, a weak positive relationship between the two variables.
	D. t = 4.65, a strong positive relationship between the variables.

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To determine whether four populations are equal, a sample from each population was selected at random and using the Kruskal-Wallis test, H was computed to be 2.09. What is our decision at the 0.05 level of risk?

	A. Fail to reject the null hypothesis because 0.05 < 2.09
	B. Fail to reject the null hypothesis because 2.09 < 7.815
	C. Reject the null hypothesis because 7.815 is > 2.09
	D. Reject the null hypothesis because 2.09 > critical value of 1.96

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A soap manufacturer is experimenting with several formulas of soap powder and three of the formulas were selected for further testing by a panel of homemakers.  The ratings for the three formulas are as follows:

 

A	35	36	44	42	37	40
B	43	44	42	32	39	41
C	46	47	40	36	45	49

 

What is the value of chi-square at the 5% level of significance?

	A. 6.009
	B. 6
	C. 5.991
	D. 5

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Which of the following values of Spearman’s coefficient of rank correlation indicates the strongest relationship between two variables?

	A. –0.91
	B. –0.05
	C. +0.64
	D. +0.89

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Suppose ranks are assigned to a set of data from low to high with $10 being ranked 1, $12 being ranked 2, and $21 being ranked 3. What ranks would be assigned to $26, $26 and $26?

	A. 4, 5, 6
	B. 4, 4, 4
	C. 5, 5, 5
	D. 5.5, 5.5, 5.5

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Two movie reviewers gave their ratings (0 to 4 stars) to ten movies released this past month as follows:

Movie	A	B	C	D	E	F	G	H	I	J
S’s Rating	4	2	3.5	1	0	3	2.5	4	2	0
T’s Rating	3	3	3	2.5	1.5	3.5	4	3	2	1

What is the rank order correlation?

	A. 48
	B. 0.7091
	C. 2.306
	D. 2.844

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What is a requirement that must be met before the Kruskal-Wallis one-way analysis of variance by ranks test can be applied?

	A. Populations must be normal or near normal
	B. Samples must be independent
	C. Population standard deviations must be equal
	D. Data must be at least interval level

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