A random sample of 54 year olds attending day care centers p

A random sample of 54 year olds attending day care centers provied a yearly tuition average of $3914 and population standard deviation of $645. Find the 95% confidence of the true means.

Solution

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 =3914 -1.96*645/sqrt(54)=3741.964

So the upper bound is

xbar + Z*s/vn=3914 +1.96*645/sqrt(54)=4086.036