Question

Which of the following situations could cause bias in the results of a telephone survey?

1) The person who answered the phone refused to participate
2) A phone number in the sample was found to be 'not in service' or 'disconnected.'
3) There was no answer, so the interviewer gave up and called someone else.
4) All of the above could cause bias in the results of the survey.
5) Two of the above could cause bias in the results of the survey.

Answer 1

Refusal to participate, 'not in service' or 'disconnected' numbers, and no answer and interviewer giving up can all cause bias in the results of a telephone survey.

Step-by-step explanation:

Biases in the results of a telephone survey can occur due to various situations. In the given options, all of them have the potential to cause bias in the survey results.

1. Refusal to participate: When a person who answers the phone refuses to participate, it can lead to a biased sample as those who refuse may have different views than those who agree to participate.
2. 'Not in service' or 'disconnected' numbers: If a phone number in the sample is found to be 'not in service' or 'disconnected', it can result in the exclusion of certain individuals from the survey, potentially introducing bias.
3. No answer and interviewer giving up: If there is no answer and the interviewer gives up without making further attempts, it can lead to an incomplete sample, potentially biasing the results.

Therefore, option 4) is correct, stating that all of the above situations could cause bias in the results of the survey.