A survey is conducted to determine the proportion of young adults who earn less than $15,000.Two sampling methods are being considered.Method A involves standing on a downtown street corner and randomly picking several young adults to interview every 10 minutes during a 12-hour period.Method B involves posting the question on several popular young adult Websites; the viewer simply has to click on one of two possible answers to participate.

1. State a possible source of bias for Method A, and describe how it may affect the results.
2. State a possible source of bias for Method B, and describe how it may affect the results.