A team of health research wants to investigate whether havingregular lunch break improves working adults’ sleep. A group of 85adults with a full-time job were recruited in the study, theyreported average hours of sleep in the past week, committed tohaving a 1-hour, out-of-office, work-free lunch break each day for3 months, and, at the end of the study, reported average hours ofsleep in the past week. The mean difference in hours of sleepbefore and after the study was 3 with a standard deviation of 0.9.Which one of the following statements is INCORRECT? (Set alphalevel at 0.05.)
| The decision should be to reject the null hypothesis. |
| The null hypothesis is that hours of sleep remain the samebefore and after the study. |
| The obtained test statistic is 3.073. |
| The degrees of freedom is 84. |
