Question

Identify the sampling techniques​ used, and discuss potential sources of bias​ (if any). Explain. In​ 1965, researchers used random digit dialing to call 1300 people and ask what obstacles kept them from buying insurance.

Answer 1

The researchers used random digit dialing to call 1300 people and ask about obstacles to buying insurance. Potential sources of bias include phone access, cell phone exclusion, and non-response bias.

Step-by-step explanation:

The sampling technique used in this study is random digit dialing. The researchers randomly generated phone numbers and called 1300 people. This method allows for the inclusion of both listed and unlisted phone numbers, increasing the chances of reaching a diverse sample.

However, there are potential sources of bias in this study. One bias could be the fact that not everyone has a telephone, which excludes those without phone access from the sample. Additionally, cell phone numbers are often not listed in published directories, so individuals who only have cell phones may be underrepresented. Lastly, some people may not be at home at the time of the call, leading to non-response bias.

Answer 2

For this case, the method used would be simple random sampling since random digit dialing assumes that all possible people in the population have the same probability of being chosen.

We may have a non-response bias, because if a selected person does not choose the phone, we have no answers to the questions and there is no data available.

We may also have under coverage bias because some people may not have a phone and in this case these people would be excluded from the study

Step-by-step explanation:

For this case is important to remember the different types of sampling methods

Simple random sampling is a method where we select a sample size n and each individual in the population are equally likely to be selected.

Stratified random sampling is a method on which we select samples from subgroups of the population usually called strata.

Convinience sampling is a method that use a random number so select the sample

Cluster sampling is a method that separates the population in natural subgroups with no intersection between them and some of the groups are selected for the sample.

For this case, the method used would be simple random sampling since random digit dialing assumes that all possible people in the population have the same probability of being chosen.

Sources of bias

We may have a non-response bias, because if a selected person does not choose the phone, we have no answers to the questions and there is no data available.

We may also have under coverage bias because some people may not have a phone and in this case these people would be excluded from the study