Question 2. [7 marks] [Chapter 4] (a) (h) (c) (d) (e) (f) A banker is interested in assessing the performance of staff at a particular branch. She is considering 3 different methods of collecting data on this. Method 1: For two weeks, have signs in the branch requesting that customers ll in survey forms available from the counter by the tellers and then place the completed forms in a box by the entrance. Method 2: For two weeks, each employee would ask every lu' customer they deal with if they were willing to ll in a survey. If so, give them a survey form to complete and ask them to post the completed form in a box by the entrance. Method 3: Use the bank's records to take a random sample of 500 people with accounts at the branch and post a questionnaire to those selected asking them to ll in and return it. People who returned the survey would go into a draw to have $100 deposited into their account. For which of the methods, if any, is non-response bias a potential problem? [1 Mark] For which of the methods, if any, is Self-selection bias a potential problem? [1 Mark] Which of the methods, if any, is subject to sampling errors? [1 Mark] {D Give an example of why there may be selection bias using Method 1. [1 Mark] {ii} Give an example of why there may be selection bias using Method 3. [1 Mark] What type of bias would the offer of the prize draw in Method 3 be trying to minimise? [1 Mark] Describe another potential source of bias will] method 1 that has not already been discussed in parts (a) to (e) above. [1 Mark]