In a study to see if a prenotification letter had an effect on response rate to a survey, 5018 physicians were sent a prenotification letter prior to being sent a survey. Of those, 2570 did respond to the survey. At the same time, 5029 physicians were mailed the survey with no prenotification letter, and 2645 responded. (a) What null and alternative hypotheses are of interest here? What two statistical procedures are appropriate for testing this null hypothesis? (b) Carry out both tests.

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