Researchers would like to estimate the mean cholesterol level ? of a particular variety of monkey that is often used in laboratory experiments They would like their estimate to be within 05 milligrams...

 Researchers would like to estimate the mean cholesterol level ? of a particular variety of monkey that is often used in laboratory experiments They would like their estimate to be within 05 milligrams per deciliter (mg/dl) of the true value of ? at a 90% confidence level A previous study involving this variety of monkey suggests that the standard deviation of cholesterol level is about 468 mg/dl What sample size is needed to ensure the margin of error is no more than 05 mg/dl at 90% confidence?

(A) 15

(B) 16

(C) 237

(D) 238

(E) 337