Question

A researcher investigates whether daily exercise decreases long-term stress levels. On a national survey, the mean stress level of those who do not exercise is 8.5. The stress score rating is 0 to 10, whereby higher scores are associated with higher stress levels. The researcher recruited nine (9) participants who exercised daily for two weeks and recorded the following stress scores: 5, 5, 4, 3, 6, 2, 9, 4, 6

Showing calculations where necessary:

a) State the null and the alternative hypotheses

b) Calculate the t obtained value

c) What is the number of df?

d) Using α = 0.05, determine t critical value and interpret the results

Answer 1

Given,

The sample values of samples is,

5

5

4

3

6

2

9

4

6

a)

b)

t = -5.3428

c)

The number of df,

df = n - 1 = 8

d)

The t critical value for α = 0.05 is -1.8595. Since the t value is lesser the critical value we reject the null hypothesis.

We conclude that daily exercise decreases long-term stress levels