An article reported the results of a peer tutoring program to help mildly mentally retarded children learn to read. In the experiment, the mildly retarded children were randomly divided into two groups: the experimental group received peer tutoring along with regular instruction, and the control group received regular instruction with no peer tutoring. There were n1= n2= 30children in each group. The Gates–MacGintie Reading Test was given to both groups before instruction began. For the experimental group, the mean score on the vocabulary portion of the test was 
, with sample standard deviation s1= 49.1. For the controlgroup, the mean score on the same test was 
, with sample standard deviation s2= 50.9. Use a 5% level of significance to test the hypothesisthat there was no difference in the vocabulary scores of the two groups beforethe instruction began.
