A health centre randomly selects 300 patients from its current patient list and sends each one a questionnaire about appointment waiting times. Only 54 patients return the questionnaire. Of those who respond, 38 say that waiting times are too long.
Calculate the proportion of respondents who say that waiting times are too long.
Explain why the 300 patients form a simple random sample but the 54 respondents may not.
Explain why using the response in part (a) to make an inference about all patients may be unreliable.
Suggest one action the health centre could take to reduce this problem.