Question

Assume that adults have IQ scores that are normally dostributed with a mean of u=97.4 and a standard deviation of o=23.8. Find the probability that a randomly selected adult has an IQ less than 132.7. The probability that a randomly selected adult has an IQ greater than 132.7 is ?

Answer 1

(a)

= 97.4

= 23.8

To find P(X<132.7):

Z = (132.7 - 97.4)/23.8 = 1.4832

Table of Area Under Standard Normal Curve gives area = 0.4306

So,

P(X<132.7) = 0.5 + 0.4306 = 0.9306

So,

Answer is:

0.9306

(b)

= 97.4

= 23.8

To find P(X>132.7):

Z = (132.7 - 97.4)/23.8 = 1.4832

Table of Area Under Standard Normal Curve gives area = 0.4306

So,

P(X>132.7) = 0.5 - 0.4306 = 0.0694

So,

Answer is:

0.0694