Chapter 1: Q1. (page 9)
Online Medical Info. USA Today posted this question on its website: 鈥淗ow often do you seek medical information online?鈥 Of 1072 Internet users who chose to respond, 38% of them responded with 鈥渇requently.鈥 What term is used to describe this type of survey in which the people surveyed consist of those who decided to respond? What is wrong with this type of sampling method?
Short Answer
These types of surveys are termed voluntary response samples and are biased.