6.39. A study considered the effects of a special class designed to improve children's verbal skills. Each child took a verbal skills test before and after attendingtheclassforthree weeks. Lety = second exam score — first exam score. The scores on y for a random sample of four children having learning problems were 3, 7, 3. 3. Conduct inferential statistical methods to determine whether the class has a positive effect. Summarize your analyses and interpretations in a short report. {Note: The scores could improve merely from the students feeling more comfortable with the testing process.

A more appropriate design would also administer the exam twice to a control group that does not take the special class, comparing the changes for the experimental and control groups using methods of Chapter 7.)