How did the two groups of toddlers (non-nappers and nappers) compare descriptively in terms of nighttime sleep duration on average (which group sleeps longer at night on average and by how much)? Why was it reasonable to produce the pooled confidence interval over the general (unpooled or Welch's) interval?
Based on the pooled 95% confidence interval, does it appear that the population mean amount of nighttime sleep for non-nappers is different from that for nappers?
Two Sample t-test
data: nappingstudy$nightsleep by nappingstudy$napstatus
t = 2.8409, df = 18, p-value 0.01084
alternative hypothesis: true difference in means is not equal to theta
95% confidence interval:
17.91298 119.62302
sample estimates:
mean in group no mean in group yes
675.040 606.272
A friend of yours works at a daycare. When you had lunch together last week, the conversation turned to taking naps. Your friend was commenting on how one parent requested that the daycare staff not let their child take a nap during the day as it was making them stay up too late at night. Your friend recently read an article which presented the results of a study that examined differences in a number of sleep variables between healthy, normally developing napping and non-napping toddlers.
The study setup consisted of recruiting families in the Providence, RI area. Some of the initial participants were excluded due to having traveled across time zones within 3 months of the study or regular use of medications that were known to influence sleep. The 20 participants were healthy, normally developing toddlers with no sleep or behavioral problems. These children were categorized as napping or non-napping based upon parental report of children's habitual sleep patterns.