Question

In Born together—Reared apart: the Landmark Minnesota twin study (2012), 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. The Excel Online file below contains 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). Construct a spreadsheet to answer the following questions.

SAT Score No Siblings	SAT Score With Siblings
476	407
615	573
564	625
372	471
375	451
432	442
540	477
572	499
472	464
640	654
538	435
638	630
546	450
634	589
536	537
586	657
529	532
541	593
539	570
629	674

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?

(to 2 decimals)

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.

(, ) (to 2 decimals)

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.

p-value is ____ (to 4 decimals)

At , a = 0.01, what is your conclusion?

_________conclude that there is a difference between the mean scores for the no sibling and with sibling groups.

Answer 1