Question

A laboratory tested twelve chicken eggs and found that the mean amount of cholesterol was 199 milligrams with s = 16.5 milligrams. Construct a 95% confidence interval for the true mean cholesterol content of all such eggs.

Answer 1

The 95% C.I will be given as follows:
mean=199
standard deviation=16.5
n=12
thus:
value of z corresponding to 95% is 1.96, thus the 95% C.I will be found as follows:
μ+/-z(σ/√n)
thus plugging in the values we get:
199+/-1.96(16.5/√12)
=199+/-9.3358
Answer: 199-9.3358≤x≤199+9.3358