Chapter 10.5, Problem 12IP

To determine

To check: Whether the conclusion made by the store manager is valid.

Answer to Problem 12IP

The manager’s conclusion is valid.

Explanation of Solution

Given information: The customers are randomly selected and the data surveyed on milk preference of the customers is given. The store manger decided 40% of milk is low fat milk.

Calculation:

The customers are chosen in a random manner. So, the sampling method is valid.

The number of customers preferring skim milk $=\text{ 88}$

The number of customers preferring low fat milk $=\text{ 92}$

The number of customers preferring whole milk $=60$

So total number of customers surveyed = $88+92+60=240$

As 92 preferred low fat, the percentage of customers prefer low fat milk can be found by,

  $\frac{92}{240}=38.3\%$

So, 38.3% prefer low fat milk. The store manager approximated it as 40%. Since the difference is low, the store manager’s conclusion can be accepted.

So his conclusion is valid.