Chapter 12.7, Problem 56STP

To determine

To find :How many were driving less than $33$ miles / hour.

Answer to Problem 56STP

  $\text{68}$

Explanation of Solution

Given information :

We know that, the given data is $\overline{x}=37,s=4$ sample of $\text{425}$ cars.

Formula Used:

Empirical rule.

Calculation:

As $\text{33}$ miles / hour with in $\text{1}$ standard deviation to the left of mean. We use empirical rules also sum up number of probabilities to left of $\text{1}$ standard deviation.

So, expected number = $\text{425 × 0}\text{.16 = 68}$