a study ia conducted to compare an experimental treatment with a control treatment i reducing join pain in patients with arthritis. 200 patients are randomly assigned to the treatment group or contral. of the 100 patients assigned to the treatment group, 54 reported improvement in thier symtopms. ofthe 100 patients assigned to the control group, 42 reported imporvement in their symptoms. test the claim that the proportion of the people reporting imporvement was higher amoung the experimental treatment group than the control treatment. use z= 1.96