Question

A team of health research wants to investigate whether having regular lunch breaks improves working adult's sleep. a group of 103 adults with a full- time job was recruited I the study, they reported average hours of sleep in the past week, committed to having a 1 hour out of office work-free lunch break each day for 3 months and at the end of the study reported average hours of sleep in the past week. the mean difference in hours of sleep before and after the study was 3 with a standard deviation of 0.9 which one of the following statements is incorrect? set alpha level at 005

a. decision should be to reject the null hypothesis

b. the obtained test static is 3.383

c. the degree of freedom is 102

d. the null hypothesis is that hours of sleep remain the same before and after study.