Researchers were looking into the effect of lack of sleep on exam scores. They asked students to come in under normal sleep conditions and take an exam. They had the same students come back the next day without having slept the night before and take another exam. The results are below:

No sleep Sleep

85 98

78 81

68 73

50 69

1: a) What are the null and research hypotheses?

b) Is this a one-tail or a two-tail test?

c) What test should we use?

d) What are the df?

e) What are the critical t-values

f) Calculate t

g) Should we reject or fail to reject the null hypothesis? What does this mean for sleep and exam-taking?

In a follow-up study researchers hadseparategroups sleep either 0, 4 or 8 hours of sleep. Using the following chart answer the questions below. Use appropriate statistical techniques and report results.

0 sleep 4 Hours sleep 8 hours sleep

48 52 85

65 69 78

66 71 80

59 81 87

45

2) Did the group with 0 sleep score Lower than the group with 8 hours of sleep?

3) Did the group with 4 hours sleep score higher than the group with 0 hours sleep?

4) Is there a difference between 4 and 8 hours sleep?