Chapter 9.1, Problem 9.2E

a)

To determine

To find the population.

Answer to Problem 9.2E

Population is “all people who wash hands in a public school”.

Explanation of Solution

Given:

More than 90% of people surveyed say they always wash their hands after using public restrooms. But observers posted in public restrooms found that only 4679 of 6076 observed individuals actually washed their hands.

First need to understand about sample and population.

Population: It is the set of all the possible individuals possessing the characteristic of interest in a study.

Sample: it is the subset of population on which, the actual study performed and from which, the necessary measurements are taken.

Here, population is “all people who wash hands in a public school”.

b)

To determine

To find the meaning of population proportion.

Answer to Problem 9.2E

Population proportion is the

Explanation of Solution

Given:

More than 90% of people surveyed say they always wash their hands after using public restrooms. But observers posted in public restrooms found that only 4679 of 6076 observed individuals actually washed their hands.

In this study, population proportion is the number of individuals who washed their hands compared to the number of all individuals observed.

c)

To determine

To find sample proportion.

Answer to Problem 9.2E

Sample proportion is 0.72

Explanation of Solution

Given:

More than 90% of people surveyed say they always wash their hands after using public restrooms. But observers posted in public restrooms found that only 4679 of 6076 observed individuals actually washed their hands.

A sample proportion is the ratio of number of successes and numbers in the sample.

Therefore,

  $\widehat{p}=\frac{4679}{6076}=0.77$