(d) Gastric freezing involves inserting a balloon down the throat and lling it with nitrogen. It has been used to treat ulcers. 30 ul- cer patients underwent gastric freezing, and of those 25 reported improvement of symptoms after the procedure. Can we conclude from this that gastric freezing is an effective treatment for ulcers? i. Yes. ii. No. iii. Yes. but the data need to be analyzed carefully to validate results