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company that sponsors LSAT prep courses would like to be able to claim that thei

ID: 3320879 • Letter: C

Question

company that sponsors LSAT prep courses would like to be able to claim that their courses improve scores by at least 3 points. To test this, they take a sample of 8 people, have each take an initial diagnostic test, then take the prep course, and then take a post-test after the course. The test results are below (scores are out of 100):

We want to know if there is evidence, at an =0.05=0.05 level of significance, to conclude that the prep course improves scores by at least 3 percentage points. Consider taking

Post-test score - Initial test score


for each person (so the value is >0 if they improved). Let dd be the mean of all such values in the population of all people who take the prep course.

1. Assume that a histogram of the score differences is approximately bell-shaped. The p-value is ____? (USE CALCULATOR VALUE)

person initial test Post test 1 74 87 2 66 76 3 72 83 4 72 73 5 77 77 6 70 78 7 69 68 8 75 85

Explanation / Answer

The statistical software output for this problem is:

Paired T hypothesis test:
D = 1 - 2 : Mean of the difference between Post test and initial test
H0 : D = 3
HA : D > 3
Hypothesis test results:

Hence,

1. p - Value = 0.0597

Difference Mean Std. Err. DF T-Stat P-value Post test - initial test 6.5 1.9730325 7 1.7739191 0.0597