Age of First Marriage Part I The National Survey of Family G

Age of First Marriage, Part I: The National Survey of Family Growth conducted by the Centers for Disease Control gathers information on family life, marriage and divorce, pregnancy, infertility, use of contraception, and men

Solution

Since the sample size is larger than 30, we can use normal distribution approximated. So all assumptions are satisfied.

Given a=1-0.95= 0.05, Z(0.025) = 1.96 (from standard normal table)

So the lower bound is

xbar - Z*s/vn=23.44 -1.96*4.72/sqrt(5534) = 23.31564

So the upper bound is

xbar + Z*s/vn =23.44 +1.96*4.72/sqrt(5534) =23.56436

We have 95% confident that the population mean will be within this interval.