A study of "adverse symptoms" in users of over-the-counter pain relief medications assigned subjects at random to one of two common pain relievers: acetaminophen and ibuprofen. In all, 650 subjects took acetaminophen, and 44 experienced some adverse symptom. Of the 347 subjects who took ibuprofen, 49 had an adverse symptom. We want to assess the evidence that the two pain relievers differ in the proportion of people who experience an adverse symptom.
a. Identify the populations and parameters of interest. Then state hypotheses.
b. State and verify conditions for carrying out a significance test.
c. Calculate the test statistic and the P-value.
d. What conclusion would you draw?
e. Construct and interpret a 90% confidence interval for the size of the difference.