(i) Refusal to take part by selected sample units and failure to contact sample units in a face-to-face social survey can both contribute to survey non-responsebias. Discuss this statement and suggest ways in which the bias might bereduced.
(ii) One thousand people were selected to participate in a face-to-face survey. Ofthe thousand, 725 were at home at the first attempt to contact them but 52 ofthese refused to take part. One call-back was made to each person missed atthe first attempt, and 30 of these people were not at home at the time of call.Of those that were at home, 49 refused to take part in the survey. Calculate there sponse rate at the first contact, the response rate at the second contact and the overall response rate.