A study of elephants is conducted to determine the average weight of a certain subspecies of elephants. The standard deviation for the population is 1500 pounds. At a 95% level, how many elephants need to be weighed so the average weight will be accurate to within 250 pounds?
A) 139
B) 165
C) 196
D) 324

Question

Quizplus · Accepted Answer

The sample size needed to achieve the desired accuracy can be calculated using the formula:n = (Z^2 * s^2) / e^2where:n is the sample sizeZ is the z-score for the desired confidence levels is the standard deviation of the populatione is the margin of errorPlugging in the given values, we get:n = (1.96^2 * 1500^2) / 250^2n = 138.24Since we cannot have a fraction of an elephant, we round up to the nearest whole number, which is 139. Therefore, the correct answer is A) 139.

A Study of Elephants Is Conducted to Determine the Average