Belsky, Weinraub, Owen, and Kelly (2001) reported on the effects of preschool childcare on the development of young children. One result suggests that children who spend more time away from their mothers are more likely to show behavioral problems in kinder- garten. Using a standardized scale, the average rating of behavioral problems for kindergarten children is m = 35. A sample of n =16 kindergarten children who had spent at least 20 hours per week in child care during the previous year produced a mean score of M = 42.7 with a standard deviation of s=6.
a. Are the data sufficient to conclude that children with a history of childcare show significantly more behavioral problems than the average kindergarten child? Use a one-tailed test with a = .01.
b. Compute the 90% confidence interval for the mean rating of behavioral problems for the popu- lation of kindergarten children who have a history of daycare.
c. Write a sentence showing how the outcome of the hypothesis test and the confidence interval would appear in a research report.