Question

A study in El Paso, Texas, looked at driving after only sleeping 5 hours or less. Drivers were observed at randomly chosen convenience stores. After they left their cars, they were invited to answer questions that included questions about how often they drove after having slept only 5 hours or less. In all, 75% said they very rarely drove if they had slept 5 hours or less. However, among those surveyed, 61.5% reported getting less than 5 hours of sleep the night before. Explain the reason for the bias observed in responses to the survey.

Selected Answer:	Bias could be due to the small number of drivers observed.
Answers:	Bias could be due to the small number of drivers observed.
	Many of the drivers may have been students.
	The convenience store may not have been representative of all stores.
	It is response bias due to the negative perception of driving on very little sleep (5 hours or less).

WHy is this right and why was my answer wrong?

Answer 1

The correct option is

"It is response bias due to the negative perception of driving on very little sleep (5 hours or less)."

As the drivers will try to hide that they drove even if they slept for 5 hours or less, since driving in such a condition is dangerous, as in such cases accidents are prone to happen.

Wrong Options

1) Bias could be due to the small number of drivers observed.

As in the questions the sample size is not given only their proportion is given

2)  Many of the drivers may have been students.

There is no information about a driver being a student

3)  The convenience store may not have been representative of all stores.

The stores are chosen at random, so there is no case of Bias in it