Question

You wish to test the following claim ( H a ) at a significance level of α = 0.005 . For the context of this problem, μ d = μ 2 − μ 1 where the first data set represents a pre-test and the second data set represents a post-test. H o : μ d = 0 H a : μ d > 0 You believe the population of difference scores is normally distributed, but you do not know the standard deviation. You obtain pre-test and post-test samples for n = 197 subjects. The average difference (post - pre) is ¯ d = 1.2 with a standard deviation of the differences of s d = 5.5 .

What is the critical value for this test? (Report answer accurate to three decimal places.) critical value =

What is the test statistic for this sample? (Report answer accurate to three decimal places.test statistic =

The test statistic is...

• in the critical region
• not in the critical region

This test statistic leads to a decision to...

• reject the null
• accept the null
• fail to reject the null

As such, the final conclusion is that...

• There is sufficient evidence to warrant rejection of the claim that the mean difference of post-test from pre-test is greater than 0.
• There is not sufficient evidence to warrant rejection of the claim that the mean difference of post-test from pre-test is greater than 0.
• The sample data support the claim that the mean difference of post-test from pre-test is greater than 0.
• There is not sufficient sample evidence to support the claim that the mean difference of post-test from pre-test is greater than 0.

Answer 1

The statistical software output for this problem is :

critical value =2.839

test statistic = 3.062

The test statistic is in the critical region .

reject the null

There is sufficient evidence to warrant rejection of the claim that the mean difference of post-test from pre-test is greater than 0.