Due to prior studies a nutritionist is willing to assume tha

Due to prior studies, a nutritionist is willing to assume that the standard deviation of the weekly calorie consumption in adults in a particular community is 100 g.

How large a sample is needed to estimate mean calorie consuption in the community with a margin of error 10 g at 95% confidence? (Show your work).

Solution

Compute Sample Size
n = (Z a/2 * S.D / ME ) ^2
Z/2 at 0.05% LOS is = 1.96 ( From Standard Normal Table )
Standard Deviation ( S.D) = 100
ME =10
n = ( 1.96*100/10) ^2
= (196/10 ) ^2
= 384.16 ~ 385