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% confidence in the results?
A)4,239
B)283
C)212
D)131
E)66

Question

Quizplus · Accepted Answer

The sample size needed for a confidence interval is given by 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 allowable errorIn this case, we have:Z = 2.576 (for a 97% confidence level)s = 15e = 0.5Plugging these values into the formula, we get:n = (2.576^2 * 15^2) / 0.5^2n = 4,239Therefore, the correct answer is A.

On a Standard IQ Test,the Standard Deviation Is 15