QUESTION 1

A randomly select group of subjects is involved in a study, and each subject was observed twice, before and after a treatment to see if there is any difference in their heart performance rates due to this treatment. The data is listed in the table below.

Subject	Before	After
1	3.5	4.0
2	2.8	3.1
3	3.2	3.3
4	2.9	3.0
5	3.3	3.7
6	3.1	3.2
7	2.8	3.0
8	3.3	3.2
9	3.2	3.8

Which of the followings is(are) correct if the Wilcoxon Signed Rank Test is performed for this analysis to see if there is significant effect from the treatment? (There are two correct answers.)

	A.	At 1% level of significance, there is significant difference in heart performance rates before and after the treatment was administrated.
	B.	At 1% level of significance, there is no significant difference in heart performance rates before and after the treatment was administrated.
	C.	At 5% level of significance, there is no significant difference in heart performance rates before and after the treatment was administrated.
	D.	At 5% level of significance, there is significant difference in heart performance rates before and after the treatment was administrated.

5 points

QUESTION 2

A research team wishes to test whether there is a statistically significant difference in average systolic blood pressures between two populations. The systolic blood pressures were measured for two samples taken independently from the two populations, and are listed below. If the Wilcoxon Rank Sum test is used, which of the following is the correct? Control ---- 144 152 155 149 151 148 Treatment - 133 150 148 145 134 147

	A.	The p-value of the test is 27.5.
	B.	The p-value of the test is 6.5.
	C.	The p-value of the test is .065.
	D.	The p-value of the test is .034.

5 points

QUESTION 3

A researcher wishes to see if the average of the weight of a certain population is greater than 190 lbs. The researcher realized that the distribution of weights for this population is symmetrically but not normal. Which of the following test procedure is proper for this test?

	A.	Wilcoxon Rank Sum Test
	B.	Kruskal Wallis test for ANOVA.
	C.	Wilcoxon Signed Rank Test
	D.	Friedman Test for Randomized Block Design.

5 points

QUESTION 4

In a random sample of 1600 people, who are asked to choose between two policies; 880 choose policy A and 720 did not A. If one wishes to test whether there is more than 50% of the people in favor of policy A, which of the following statements is true?

	A.	THe p-value is 0.023.
	B.	The p-value is 0.046.
	C.	The p-value is 0.092.
	D.	The p-value is less than 0.001.

5 points

QUESTION 5

In a study, researchers wish to understand the difference between four training programs to train individuals for a new task. Twelve subjects with similar ability were randomly selected from several health departments in Ohio. Training programs were randomly assigned to the twelve subjects so that each program has three subjects. The evaluations on proficiency of these twelve subjects in performing this new task were recorded as in the following table. The higher the score the better the performance.

Program 1	Program 2	Program 3	Program 4
23	34	16	17
25	38	23	20
26	31	24	21

If the Kruskal-Wallis test is used for testing whether there is statistically significant difference between the 4 programs based on the scores above, which of the following is(are) correct statement(s)? (There are two correct answers.)

	A.	Statistically, there is significant difference between the mean scores at 5% level of significance.
	B.	Statistically, there is no significant difference between the mean scores at 10% level of significance.
	C.	Statistically, there is no significant difference between the mean scores at 5% level of significance.
	D.	Statistically, there is no significant difference between the mean scores at 1% level of significance.
	E.	Statistically, there is significant difference between the mean scores at 1% level of significance.

5 points

QUESTION 6

Two independent random samples were taken from two populations to compare their median cholesterol levels. The data are listed below: Sample 1: 117, 115, 135, 116, 141 Sample 2: 151, 118, 146, 147, 155 Which of the followings is(are) correct if Wilcoxon Rank Sum Test is used? (There are two correct answers.)

	A.	There is statistically significant difference between the median cholesterol levels of the two populations at 1% level of significance.
	B.	There is no statistically significant difference between the median cholesterol levels of the two populations at 1% level of significance.
	C.	There is statistically significant difference between the median cholesterol levels of the two populations at 5% level of significance.
	D.	There is no statistically significant difference between the median cholesterol levels of the two populations at 5% level of significance.