Question

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1. Identify the kind of sampling was implemented in the following scenarios.
   1. Police at a sobriety checkpoint pull over every fifth car to determine whether the driver is sober.
   2. A pollster obtains a list of all the residential addresses in a certain town and uses a computer random number generator to choose 150 of them. The pollster visits each of the 150 households and interviews all the adults in each household about their television viewing habits.
   3. Officials at a metropolitan transit authority want to get input from people who use a certain bus route about a possible change in the schedule. They randomly select 5 buses during a certain week and poll all riders on those buses about the change.
   4. A smartphone app produces a message requesting customers to click on a link to rate the app.
2. Imagine that you are asked to determine students’ opinions at your school about different types of contraception or birth control methods. Describe how you could go about getting a sample of each of the following types: simple random sample, sample of convenience, voluntary response sample, stratified sample, cluster sample, systematic sample.

Answer 1

Solution:

a)Police at a sobriety checkpoint pull over every fifth car to determine whether the driver is sober.

Answer: Systematic sampling

In systematic sampling, samples are chosen from a larger population according to a random starting point but with a fixed, periodic interval.

b)A pollster obtains a list of all the residential addresses in a certain town and uses a computer random number generator to choose 150 of them. The pollster visits each of the 150 households and interviews all the adults in each household about their television viewing habits.

Answer: Cluster sampling

In cluster sampling, the researchers divides the population into separate groups called clusters. Then, a simple random sample of clusters is selected from the population.

c)Officials at a metropolitan transit authority want to get input from people who use a certain bus route about a possible change in the schedule. They randomly select 5 buses during a certain week and poll all riders on those buses about the change.

Answer: Cluster sampling

d)A smartphone app produces a message requesting customers to click on a link to rate the app

Answer: Voluntary response sample

Voluntary response sample is made up of persons who volunteer to take part in research surveys.