Question

Assume that adults have IQ scores that are normally distributed with a mean of 101.3 and a standard deviation of 22.1. Find the probability that a randomly selected adult has an IQ greater than 145.0. (Hint: Draw a graph.) The probability that a randomly selected adult from this group has an IQ greater than 145.0 is (Round to four decimal places as needed.)

Answer 1

Solution :

Given that ,

mean = $\mu$ = 101.3

standard deviation = $\sigma$ = 22.1

P(x >145.0 ) = 1 - P(x <145.0 )

= 1 - P[(x - $\mu$ ) / $\sigma$ < (145.0 - 101.3) /22.1 ]

= 1 - P(z <1.98 )

Using z table,

= 1 -0.9761

=0.0239