Chapter 7, Problem 7.19P

$\boxed{SOC}$ A researcher is studying changes in the student body at her university and has selected a random sample of 163 from the freshman class. The table below compares their characteristics to the student body as a whole. Which differences are significant?

	Variable	Freshmen	All Students
a.	Proportion Republican	$P_s=0.44$	$P_u=0.49$
b.	Proportion majoring in math and science	$P_s=0.17$	$P_u=0.09$
c.	Average family income	$\begin{array}{c}\bar{X}=63,542\\ s=1568\end{array}$	$\mu =59,235$
d.	Average number of siblings	$\begin{array}{c}\bar{X}=0.9\\ s=0.2\end{array}$	$\mu =1.2$
e.	Average number of telephone calls to parents per week	$\begin{array}{c}\bar{X}=1.5\\ s=0.4\end{array}$	$\mu =0.4$
f.	Average number of close friends living on campus	$\begin{array}{c}\bar{X}=4.5\\ s=0.3\end{array}$	$\mu =7.8$