A study published by the National Cancer Institute (V. Kirsh et al., 2005) reported on the effect of lycopene and tomato product intake on the risk of prostate cancer. The study followed the health history and dietary habits of 29,361 men during an average of 4.2 years of follow-up over which time 1338 of the men developed prostate cancer. Results indicated that there was no evidence that lycopene consumption protects from prostate cancer except for those with a family history of prostate cancer. In this case, risks tended to be lower with greater consumption of spaghetti/ tomato sauce (relative risk for at least two servings per week versus less than one serving per month = 0.68, 95% CI = 0.31 to 1.51, P-value = 0.12). Explain how to interpret the
(a) Relative risk value and
(b) Confidence interval.