# math

posted by
**eniko**
.

You are on a jury in a murder trial. After a few days of testimony, your probability for the defendant being guilty is .80. Then, at the end of the trial, the prosecution presents a new piece of evidence, just rushed in from the lab. The defendent’s blood type is found to match that of blood found at the scene of the crime, which could only be the blood of the murderer. The particular blood type occurs in 5% of the population. What should be your revised probability for the defendant’s guilt? Solve the problem first by using Bayes’ rule for probabilites, then by using Bayes’ rule for natural frequencies