Identify the sampling techniques used, and discuss potential sources of bias (if any). Explain. In 1965 , researchers used random digit dialing to call 1200 people and ask what obstacles kept them from attending sporting events. What type of sampling was used? A. Systematic sampling was used, since phone numbers were selected from a list using a fixed interval between phone numbers. B. Convenience sampling was used, since the 1200 phone numbers that were easiest to reach were selected. C. Simple random sampling was used, since each number had an equal chance of being dialed, so all samples of 1200 phone numbers had an equal chance of being selected. D. Cluster sampling was used, since the phone numbers were divided into groups, several groups were selected, and each number in those groups was called. What potential sources of bias were present, if any? Select all that apply. \( \square \) A. Individuals may have refused to participate in the sample. This may have made the sample less representative of the population. \( \square \) B. Individuals may have not been available when the researchers were calling. Those individuals that were available may have not been representative of the population. \( \square \) c. If there was a regular pattern to the numbers dialed, it is possible for the sample to not have been representative of the population.

The sampling technique used in this scenario is: **C. Simple random sampling was used, since each number had an equal chance of being dialed, so all samples of 1200 phone numbers had an equal chance of being selected.** Random digit dialing is a method that allows for the selection of phone numbers in a way that each number has an equal probability of being chosen, which aligns with the definition of simple random sampling. ### Potential Sources of Bias: 1. **A. Individuals may have refused to participate in the sample. This may have made the sample less representative of the population.** - This is a valid source of bias. If individuals refuse to participate, the sample may not accurately reflect the views of the entire population. Those who refuse might have different characteristics or opinions compared to those who agree to participate. 2. **B. Individuals may have not been available when the researchers were calling. Those individuals that were available may have not been representative of the population.** - This is also a valid source of bias. If certain demographics are less likely to be available during the times the calls are made (e.g., working individuals), the sample may skew towards those who are more available, potentially leading to an unrepresentative sample. 3. **C. If there was a regular pattern to the numbers dialed, it is possible for the sample to not have been representative of the population.** - This statement could introduce bias if the random digit dialing method inadvertently favored certain patterns or groups of numbers. However, if the method is truly random, this should not be a significant concern. Still, if there were any systematic issues in the dialing process, it could lead to bias. ### Summary: In summary, the sampling technique used was simple random sampling, and potential sources of bias include non-response from individuals, availability issues during the calling times, and any unintended patterns in the dialing process. Each of these factors could affect the representativeness of the sample and the validity of the conclusions drawn from the data collected.