Instruction 10-4
To test the effectiveness of a business school preparation course, 8 students took a general business test before and after the course. The results are given below.
$$\begin{array} { c c c }
\text { Student } & \begin{array} { c }
\text { Exam Score } \
\text { Before Course }
\end{array} & \begin{array} { c }
\text { Exam Score } \
\text { After Course (2) }
\end{array} \
& ( 1 ) & \
1 & 530 & 670 \
2 & 650 & 770 \
3 & 910 & 1,000 \
4 & 700 & 710 \
5 & 450 & 550 \
6 & 820 & 870 \
7 & 820 & 770 \
8 & 630 & 610
\end{array}$$
-Referring to Instruction 10-4,the value of the sample mean difference is __________ if the difference scores reflect the results of the exam after the course minus the results of the exam before the course.
A) 400
B) 50
C) 68
D) 0

Question

Instruction 10-4
To test the effectiveness of a business school preparation course, 8 students took a general business test before and after the course. The results are given below.
 $$\begin{array} { c c c } 
\text { Student } & \begin{array} { c } 
\text { Exam Score } \
\text { Before Course }
\end{array} & \begin{array} { c } 
\text { Exam Score } \
\text { After Course (2) }
\end{array} \
& ( 1 ) & \
 1  & 530 & 670 \ 
2 & 650 & 770 \
3 & 910 & 1,000 \
4 & 700 & 710 \
5 & 450 & 550 \
6 & 820 & 870 \
7 & 820 & 770 \
8 & 630 & 610
\end{array}$$
-Referring to Instruction 10-4,the value of the sample mean difference is __________ if the difference scores reflect the results of the exam after the course minus the results of the exam before the course.
A) 400
B) 50
C) 68
D) 0

Quizplus · Accepted Answer

The sample mean difference can be calculated by subtracting the mean of the before-course scores from the mean of the after-course scores. 
Mean of before-course scores = (57+59+66+70+72+74+77+79)/8 = 69
Mean of after-course scores = (62+71+77+81+83+85+88+92)/8 = 79
Sample mean difference = 79 - 69 = 10.
Therefore, the closest option to 10 is B) 50.

Instruction 10-4 to Test the Effectiveness of a Business School

Instruction 10-4
to Test the Effectiveness of a Business School