Question

The following data were obtained from 4 people Pre-Test Value Post-test Value 43 42 28 29 31 30 28 25 You may also assume that the sample standard deviation for the four differences is 1.6. What is the correct t-statistic and the degrees of freedom for these data

Answer 1

Test statistic = 1.25

Degree of freedom = 3

Explanation:

The following data were obtained from 4 people

Pre-Test Value Post-test Value __ d

43 ________42 _________ 1

28_______ 29 ________ - 1

31 ________30 _________ 1

28 ________ 25 _________ 3

μd = (1 + - 1 + 1 + 3) / 4 = 4 /4 = 1

The mean difference, μd = 1

The standard deviation of difference, Sd = 1.6

The test statistic = μd / (Sd / √n)

Test statistic = 1 / (1.6/2) = 1 / 0.8

Test statistic = 1.25

Degree of freedom, = n - 1 = 4 - 1 = 3