An investigation of the effectiveness of a training program

An investigation of the effectiveness of a training program to improve customer relationships included a pre-training and post-training customer survey. Seven customers were randomly selected and completed both surveys. The results follow.

What is the value of the test statistic?

Solution

Since this is an dependent t test, first find the differences:

customer

pre

post

difference

a

14

16

2

b

13

13

0

c

18

18

0

d

15

18

3

e

14

16

2

f

13

14

1

g

10

16

6

Then Find the average, dbar, and standard deviation of the difference column. These are 2 and 2.081666, respectively.

The test statistic, t = dbar/(sd/square root of n)

T = 2/(2.081666/square root of 7)

T = 2.542

Answer: 2.542