Chapter 10, Problem 42SE

Effect of Siblings on SAT Scores. In Born Together—Reared Apart: The Landmark Minnesota Twin Study (http://www.hup.harvard.edu/catalog.php?isbn=9780674055469), Nancy Segal discusses the efforts of research psychologists at the University of Minnesota to understand similarities and differences between twins by studying sets of twins who were raised separately. Below are critical reading SAT scores for several pairs of identical twins (twins who share all of their genes), one of whom was raised in a family with no other children (no siblings) and one of whom was raised in a family with other children (with siblings).

1. a. What is the mean difference between the critical reading SAT scores for the twins raised with no siblings and the twins raised with siblings?
2. b. Provide a 90% confidence interval estimate of the mean difference between the critical reading SAT scores for the twins raised with no siblings and the twins raised with siblings.
3. c. Conduct a hypothesis test of equality of the critical reading SAT scores for the twins raised with no siblings and the twins raised with siblings at α = .01. What is your conclusion?