Scores on a Standard IQ Test Are Normally Distributed with Population

Multiple Choice

Scores on a standard IQ test are normally distributed with population standard deviation 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