Question

Assume that adults have IQ scores that are normally distributed with a mean of 103.3 and a standard deviation of 16.2. Find the probability that a randomly selected adult has an IQ greater than 127.4. ​(Hint: Draw a​ graph.) The probability that a randomly selected adult from this group has an IQ greater than 127.4 is

Answer 1

Solution :

Given that ,

mean = = 103.3

standard deviation = = 16.2

P(x > 127.4) = 1 - P(x < 127.4)

= 1 - P[(x - ) / < (127.4 - 103.3) / 16.2)

= 1 - P(z < 1.4877)

= 1 - 0.9316

= 0.0684

The probability that a randomly selected adult from this group has an IQ greater than 127.4 is 0.0684