Question

18)

A laboratory tested 73 chicken eggs and found that the mean amount of cholesterol was 230 milligrams with Η=17.4 milligrams. Construct a 95% confidence interval for the true mean cholesterol content, μ,of all such eggs. A)227mg<μ<235mg B)226mg<μ<234mg C)225mg<μ<233mg D)225mg<μ<234mg

Answer 1

B) 226 mg < μ < 234 mg

Explanation:

Confidence interval for Population mean is given as below:

Confidence interval = Xbar ± t*S/sqrt(n)

From given data, we have

Xbar = 230

S = 17.4

n = 73

df = n – 1 = 72

Confidence level = 95%

Critical t value = 1.9935

(by using t-table)

Confidence interval = Xbar ± t*S/sqrt(n)

Confidence interval = 230 ± 1.9935*17.4/sqrt(73)

Confidence interval = 230 ± 4.0597

Lower limit = 230 - 4.0597 = 225.94

Upper limit = 230 + 4.0597 = 234.06

226 mg < μ < 234 mg