Question

Intelligent quotient scores are often reported to be normally distributed with (see picture)A random sample of 35 people is taken what is the probability of a random person on the street having an IQ score of less than 99? Round your answer to four decimal places if necessary

Answer 1

Normla distribution with:

mean=100

standard desviation=15

Sample: 35

The normal distribution is given by:

$P(Z<99).$

and

$z=\frac{x-\mu}{\sigma}=\frac{35-100}{15}=-4.3$

Using the z table:

$P(-4.3)=0.00002$

Answer, the probability to choose someone with IQ less than 99 is: 1-0.00002.= 0.9999.