Exhibit 7-4: A group of researchers has developed a method that they hypothesize will improve physics test scores.They randomly selected nine students to participate in their study.The nine students were administered an ACT test, trained in the new method, and then administered an alternate form of the ACT test.The following data are their scores:
$ \begin{array}{lll}\text {Subject } & {\text {Test 1 }}{} & \text {Test 2 } \ 1 & 20 & 19 \ 2 & 20 & 20 \ 3 & 24 & 21 \ 4 & 24 & 24 \ 5 & 24 & 22 \ 6 & 17 & 15 \ 7 & 18 & 15 \ 8 & 18 & 16 \ 9 & 20& 18\end{array} $
-Refer to Exhibit 7-4.What is the observed value for the chosen statistic?
A) .94
B) 1.172
C) 4.603
D) None of these are true.

Question

Exhibit 7-4: A group of researchers has developed a method that they hypothesize will improve physics test scores.They randomly selected nine students to participate in their study.The nine students were administered an ACT test, trained in the new method, and then administered an alternate form of the ACT test.The following data are their scores:
 $ \begin{array}{lll}\text {Subject } & {\text {Test 1 }}{} & \text {Test 2 } \ 1 & 20 & 19 \ 2 & 20 & 20 \ 3 & 24 & 21 \ 4 & 24 & 24 \ 5 & 24 & 22 \ 6 & 17 & 15 \ 7 & 18 & 15 \ 8 & 18 & 16 \ 9 & 20&  18\end{array} $
-Refer to Exhibit 7-4.What is the observed value for the chosen statistic?
A) .94
B) 1.172
C) 4.603
D) None of these are true.

Quizplus · Accepted Answer

The observed value for the chosen statistic is calculated using the differences between Test 1 and Test 2 scores. The differences are: 1, 0, 3, 0, 2, 2, 3, 2, 2. The mean of these differences is 1.6667, and the standard deviation is approximately 1.118. Using these, the t-statistic is calculated as 4.603.

Exhibit 7-4: a Group of Researchers Has Developed a Method