Question

4.

Hypothesis Test for Two Populations including

• t-Test for μ₁-μ₁
• t-Test for μd
• F-Test for

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 in the accompanying table.

Student	Exam Score Before Course	Exam Score After Course	Difference = After - Before
1	530	670	140
2	690	770	80
3	910	1,000	90
4	700	710	10
5	450	550	100
6	820	870	50
7	820	770	??
8	630	610	??

What is the value of the sample mean difference ( d-bar ) if the difference scores reflect the results of the exam after the course minus the results of the exam before the course?

Group of answer choices

a. 50

b. 68

c. 400

d. 0

Answer 1

Solution :

From given that ,

Student	Exam Score Before Course	Exam Score After Course	Difference = After - Before
1	530	670	140
2	690	770	80
3	910	1,000	90
4	700	710	10
5	450	550	100
6	820	870	50
7	820	770	-50
8	630	610	-20

= (140 + 80 + 90 + 10 + 100 + 50 - 50 - 20) / 8 = 50

Option a)