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.

To identify the sampling technique used and discuss potential sources of bias, let's break down the information provided: **Sampling Technique Used:** The sampling technique used in this study is **random digit dialing (RDD)**. This method involves randomly selecting phone numbers from a list of all possible phone numbers within a given area. The researchers then called these numbers to reach potential participants. Here's how RDD works: 1. Generate a list of all possible phone numbers within the target area. 2. Randomly select phone numbers from this list. 3. Call the selected phone numbers and ask the questions. **Potential Sources of Bias:** 1. **Coverage Bias**: RDD may not cover all potential participants. For example, it might miss individuals who do not have landline or mobile phones, or those who have unlisted numbers. This could lead to a sample that is not representative of the entire population. 2. **Response Bias**: Some individuals may be less likely to answer the phone or participate in the survey. This could be due to various reasons, such as being busy, not interested in the topic, or suspicious of the call. This non-response bias can lead to an unrepresentative sample. 3. **Social Desirability Bias**: Participants may answer the questions in a way that they believe is socially acceptable or desirable, rather than providing their true opinions. For example, they may be more likely to say they attend sporting events frequently to appear interested in sports. 4. **Selection Bias**: The random selection of phone numbers may not be truly random, as some numbers may be more likely to be selected than others. For example, if the list of phone numbers is not comprehensive, some areas or demographics may be overrepresented or underrepresented in the sample. 5. **Non-Random Sampling**: While RDD is a form of random sampling, it is not a purely random sample. The fact that the researchers called specific phone numbers rather than using a completely random process introduces some level of non-randomness. In summary, the sampling technique used in this study is random digit dialing, but there are several potential sources of bias, including coverage bias, response bias, social desirability bias, selection bias, and non-random sampling. These biases could affect the generalizability of the study's findings.