Chapter 9, Problem 23P

Research examining the effects of preschool childcare has found that children who spent time in day care, especially high-quality day care, perform better on math and language tests than children who stay home with their mothers (Broberg, Wessels, Lamb, & Hwang, 3997). In a typical study, a researcher obtains a sample of $n=10$ children who attended day care before starting school. The children are given a standardized math test for which the population mean is $\mu =50$ . The scores for the sample are as follows:

57. 61.49. 52. 56. 58.62. 51. 56.

a. Is this sample sufficient to conclude that the children with a history of preschool day care are significantly different from the general population? Use two-tailed test with $\alpha =.01$ .

b. Compute Cohen’s d to measure the size of the preschool effect.

c. Write a sentence showing how the outcome of the hypothesis lest and the measure of effect size would appear in a research report.