Each of the following surveys has bias. Identify the type of bias.
(a) A television survey that gives 900 phone numbers for viewers to call with their vote. Each call costs $2.00.
(b) An employer distributes a survey to her 450 employees asking them how many hours each week, on average, they surf the Internet during business hours. Three of the employees complete the survey.
(c) A question on a survey asks, “Do you favor or oppose a minor increase in property tax to ensure fair salaries for teachers and properly equipped school buildings?”
(d) A researcher conducting a poll about national politics sends a survey to a random sample of subscribers to Time magazine.