Chapter 11, Problem 2CA

(a)

To determine

To find whether the sample is biased or unbiased.

Explanation of Solution

Given:

A restaurant asks customers to participate in a survey about the food sold at the restaurant. The restaurant uses the survey that are returned.

Calculation:

It is unbiased as there is no condition specified.

(b)

To determine

To find whether the sample is biased or unbiased.

Explanation of Solution

Given:

You want to know the favorite sport of students at your school and randomly selects athletes to survey at the winter sports banquet.

Calculation:

It is biased because athletes are to survey at the winter sports banquet.

(c)

To determine

To find whether the sample is biased or unbiased.

Explanation of Solution

Given:

The owner of the store wants to know whether the store should stay open for one hour later each night. Each cashier surveys every fifth customer.

Calculation:

It is unbiased as there is no condition specified.

(d)

To determine

To find whether the sample is biased or unbiased.

Explanation of Solution

Given:

The owner of movie theatre wants to know whether the volume of is too loud. Patrons under the age of $18$ are randomly surveyed.

Calculation:

It is biased because patrons under the age of $18$ are randomly surveyed.