Question

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, 1997).

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 u = 50. The scores for the sample are as follows:

53, 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 a two-tailed test with a = .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 test

and the measure of effect size would appear in a research report.

Answer 1