2. [2 marks] A study in El Paso, Texas, looked at seat belt use by drivers. Drivers were observed at randomly chosen grocery stores. After they left their cars, they were invited to answer questions that included questions about seat belt use. In all, 75% of drivers said they always used seat belts, yet only 61.5% were wearing seat belts when they pulled into the store parking lots. Very briefly (in 1 to 2 sentences only!) explain the reason for the bias observed in responses to the survey. And indicate what type of bias i.e. non-sampling error is this