Which statement regarding biased sampling is false?
1) online sampling is biased because only the people who happen
to visit the web site will take the survey.
2) a radio call-in survey is biased because only people who feel
strongly about the topic will respond.
3) a survey handed to every third person leaving a library is biased
because everyone leaving the library was not asked to
participate.
4) asking for experts to take a survey is biased because they may
have particular knowledge of the topic.