Question

Assume that adults have IQ scores that are normally distributed with a mean of 100 and a standard deviation of 15. Find the probability that a randomly selected adult has an IQ between 115 and 130.

          (a) .6700      (b) .1359      (c) .9082      (d) .1596      (e) .1628

5        Refer to question 4 above. Find the IQ score at Q1 or the 25^th percentile. This is the score which separates the bottom 25% from the top 75%.

          (a) 89.95      (b) 110.05     (c) 84.95      (d) .2514      (e) .7486

6        Refer to question 4 above. Find the IQ score at Q2 or the 50^th percentile. This is the score which separates the top 50% from the bottom 50%.

(a) 103         (b) 110.05     (c) 0.00        (d) 100         (e) .5000

Answer 1

Ans 4

Ans 5

a) 89.887

Ans 6

d)

100