A study in the July 7,2009 , issue of \(U S A\) TODAY stated that the
\(401(\mathrm{k})\) participation rate among
U.S. employees of Asian heritage is \(76 \%\), whereas the participation rate
among U.S. employees of Hispanic heritage is \(66 \%\). Suppose that these
results were based on random samples of 100 U.S. employees from each group.
a. Construct a \(95 \%\) confidence interval for the difference between the two
population proportions.
b. Using the \(5 \%\) significance level, can you conclude that the
\(401(\mathrm{k})\) participation rates are different for all U.S. employees of
Asian heritage and all U.S. employees of Hispanic heritage? Use the critical-
value and \(p\) -value approaches.
c. Repeat parts a and b for both sample sizes of 200 instead of 100 . Does
your conclusion change in part b?