Treating ulcers. Gastric freezing was once a recommended treatment for stomach ulcers. Use of gastric freezing stopped after experiments showed it had no effect. One randomized comparative experiment found that 28 of the 82 gastric-freezing patients improved, while 30 of the 78 patients in the placebo group improved.

(a) Outline the design of this experiment.

(b) Make a two-way table of treatment versus outcome (subject improved or not). Is there a significant relationship between treatment and outcome?

(c) Write a brief summary that includes the test result and also percentages that compare the success of the two treatments.