A researcher was interested in Aucklanders’ opinions about rates and rate increases. He  considered 3 different approaches to gathering information on this.  

Method 1: Randomly select 1,000 names from the Auckland phone book. Then hire a team of  people to phone each person on the list and interview them.  

Method 2: Place advertisements in community papers asking people to go online and fill in a  questionnaire.  

Method 3: Use council records to assemble a list of all houses currently in Auckland City.  Randomly select 1,000 houses from this list and post a questionnaire to each address asking the  oldest person living in the house to fill in and return the questionnaire.

(a) For which of the methods, if any, is non-response bias a potential problem?

(b) For which of the methods, if any, is self-selection bias a potential problem? 

(c) Which of the methods, if any, is subject to interviewer effects? 

(d) Which of the methods, if any, is subject to sampling errors? 

(e) For each of the methods, give an example of why there may be selection bias.