Exercise

# Exercise 4. Seven footers and the NBA

Someone asks you what percent of seven footers are in the National Basketball Association (NBA). Can you provide an estimate? Let's try using the normal approximation to answer this question.

Given a normal distribution with a mean `mu`

and standard deviation `sigma`

, you can calculate the proportion of observations less than or equal to a certain `value`

with `pnorm(value, mu, sigma)`

. Notice that this is the CDF for the normal distribution. We will learn much more about `pnorm`

later in the course series, but you can also learn more now with `?pnorm`

.

First, we will estimate the proportion of adult men that are taller than 7 feet.

Assume that the distribution of adult men in the world as normally distributed with an average of 69 inches and a standard deviation of 3 inches.

Instructions

**100 XP**

- Using the normal approximation, estimate the proportion of adult men that are taller than 7 feet, referred to as
*seven footers*. Remember that 1 foot equals 12 inches. - Use the
`pnorm`

function. Note that`pnorm`

finds the proportion less than or equal to a given value, but you are asked to find the proportion greater than that value. - Print out your estimate; don't store it in an object.