The probability of having prostate cancer when the PSA test is positive in part a is only .0213. The difference between P(C│+) and P(C│-) in parts a and b is relatively small. The probability of having prostate cancer when the PSA test is positive is .0213 compared to .0161 when the PSA test is negative. When the prior probability increases in part c, P(C│+) increases to .4156, but P(C│-) is also relatively high at .3478. Results similar to these are why the guidelines for when males are tested for prostate cancer and how they are treated if they test positive have changed in recent years.