Question

Which of the following is an example of stratified sampling? A poll asked a random sample of 1,327 adults whether they supported stronger gun control measures. In order to assess public attitudes on good nutrition the the first 40 people to leave a large grocery store were interviewed. Proponents of a local ballot measure conduct a survey of the city by randomly selecting 100 potential voters from each of its 18 zip codes. A sample of 37 people who came to speak before the city council on the proposed water conservation plan were surveyed. The human resources department of a large retail chain wanted to assess the job satisfaction of the retail workers. The department chose 25 of the company's stores at random, and used all of the workers in those 25 branches as the subjects for the study.

Answer 1

Answer:

"Proponents of a local ballot measure conduct a survey of the city by randomly selecting 100 potential voters from each of its 18 zip codes" is an example of  stratified sampling

Step-by-step explanation:

The stratifed samplig methos its a probabilistical method that takes all the universe studied and divide this into different groups. In this case the universe is all the population divided into the 18 zip codes).

After that, it randonbly selects the subjects of every group and generates the statistical sample.

In this case, it can be used the proportional stratified samplig where  you take the porportion of voters in every zip code and use ir¡t as the number of voters selected on every zip code.

How does it can be perform? . Let's see: For example:

• Percentaje on the total population in zip code 1: 18%
• Number of subjects of zip code 1 in the sample: 18
• and so on...

So you will have a 100 subject`s sample based on the method of proportional stratified sampling

It can also use the non proportional stratified sampling method taking the same number of subjects on every zip code.