Q8 Hi I need answers to all parts of the problem please

STA2023 Fall 2021 Sections OM8 and 1M4 Question 8, 20.CE.31 HW Score: 58.04%, 9.87 of 17 points Save Part 1 of 3 X Points: 0 of 1 Men diagnosed with cancer were randomly assigned to either undergo surgery or not. Among the 349 men who had the surgery, 16 eventually died of cancer, compared with 20 of the 346 men who did not have surgery. a) Was this an experiment or an observational study? Explain. b) Create a 95% confidence interval for the difference in rates of death for the two groups of men. c) Based on your confidence interval, is there evidence that surgery may be effective in preventing death from cancer? Explain