Question

On a normal distribution of iq test scores, with a mean of 100 and a stadard deviation of 15 points, a score of 70 would place you in approximately what percentile of the population?

Answer 1

(70 -100)/15 = -2 . . . . the z-score of a score of 70

p(z < -2) ≈ 2.3%

A score of 70 would place you in approximately the 2nd percentile.