Question

Find the indicated IQ score. The graph to the right depicts IQ scores of​ adults, and those scores are normally distributed with a mean of 100 and a standard deviation of 15.

Graph shows shaded area is .97

Answer 1

Solution:-

Given that,

mean = = 100

standard deviation = = 15

Using standard normal table,

P(Z > z) = 0.97

= 1 - P(Z < z) = 0.97  

= P(Z < z) = 1 - 0.97

= P(Z < z ) = 0.03

z =-1.88

Using z-score formula,

x = z * +

x = -1.88 * 15+100

x = 71.8