On a standard IQ test,the standard deviation is 15.How many random IQ scores must be obtained if we want to find the true population mean (with an allowable error of 0.5)and we want 97 percent confidence in the results?
A) 4,239
B) 283
C) 212
D) 131
E) 66

Question

Quizplus · Accepted Answer

The sample size needed to estimate the population mean with an allowable error of 0.5 and a confidence level of 97% is given by:n = (Z^2 * s^2) / e^2where:Z is the z-score corresponding to the desired confidence levels is the standard deviation of the populatione is the allowable errorPlugging in the given values, we get:n = (2.17^2 * 15^2) / 0.5^2 = 4,239Therefore, the correct answer is A.

On a Standard IQ Test,the Standard Deviation Is 15