P2010 HA Two population tests
Fill out and submit the accompanying answer sheet for each problem.
1. Suppose a psychologist is studying the effects of a certain motion picture on the
attitudes of people toward capital punishment. She believes that viewing the film will
cause changes in the scores of the persons viewing the film on an attitude scale. The
scores of 12 persons are:
Before: 10
After:
5
13
18
12
9
8
14
12
17
20
11
7
9
13
17
4
5
11
4
13
18
10
7
2. A study was undertaken to investigate the effectiveness of a computer aided program
for instruction in statistics. Twelve students served in a Control Group, receiving the
instruction using the old method. Fifteen students served in the Experimental Group,
receiving the new method. The results, scores (out of 100 possible) on the final exam,
are:
New: 75 80 85 90 95 85 80 75 80 85 90 95 80 75 80
Old:
80 75 75 70 80 75 70 65 80 90 75 70
3.
Two sample means are being compared. The sample sizes are not equal. Which
test must be employed?
4.
Two sample means are being compared. The scores are paired. Each score in
sample 1 is matched with a score in sample 2. What test must be employed?
5.
For which two sample test is a test of equality of population variances required
prior to choosing the appropriate t statistic?
t-tests assignment - 1
Problem 1
Name _____________________________________________________
1. Give the name of the test statistic that will be employed to test the null hypothesis.
2. Do the data meet the assumptions of the test? Provide evidence.
3. The null and alternative hypotheses.
Null
Hypothesis:______________________________________________________________
__
Alternative
Hypothesis:______________________________________________________________
____
4. What significance level will you use to separate "likely" value from "unlikely" values
of the test statistic?
Significance Level =
___________________________________________________________
5. What is the value of the test statistic computed from your data and the p-value?
Test statistic value = _________________________
6. What is your conclusion?
p-value_________________
Do you reject or not reject the null hypothesis?
7. What are the upper and lower limits of a 95% confidence interval appropriate for the
problem?
Lower Limit = ___________________
Upper Limit = ____________________
8. State the implications of your conclusion for the problem you were asked to solve.
That is, relate your statistical conclusion to the problem.
t-tests assignment - 2
Problem 2
Name _____________________________________________________
1. Give the name of the test statistic that will be employed to test the null hypothesis.
2. Do the data meet the assumptions of the test? Provide evidence.
3. The null and alternative hypotheses.
Null
Hypothesis:______________________________________________________________
__
Alternative
Hypothesis:______________________________________________________________
____
4. What significance level will you use to separate "likely" value from "unlikely" values
of the test statistic?
Significance Level =
___________________________________________________________
5. What is the value of the test statistic computed from your data and the p-value?
Test statistic value = _________________________
6. What is your conclusion?
p-value_________________
Do you reject or not reject the null hypothesis?
7. What are the upper and lower limits of a 95% confidence interval appropriate for the
problem?
Lower Limit = ___________________
Upper Limit = ____________________
8. State the implications of your conclusion for the problem you were asked to solve.
That is, relate your statistical conclusion to the problem.
3. _____________________________________________________________________
4. _____________________________________________________________________
5. _____________________________________________________________________
t-tests assignment - 3