R$4\mathrm{.}2$ Bad sampling A large high school wants to gather student opinion about parking for students on campus. It isn't practical to contact all students.

$($a$)$ Give an example of a way to choose a voluntary response sample of students. Explain how this method could lead to bias.

$($b$)$ Give an example of a way to choose a convenience sample of students. Explain how this method could lead to bias.