Mathematics Stack Exchange is a question and answer site for people studying math at any level and professionals in related fields. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

Assume that the amount of evidence against a defendant in a criminal trial is an exponential random variable X. If the defendant is innocent, then X has mean 1, and if the defendant is guilty, then X has mean 2. The defendant will be ruled guilty if X>c, where c is a suitably chosen constant. If the judge wants to be 95% certain that an innocent man will not be convicted, what should the value of c be? Enter your answer as a decimal and make sure that at least 8 digits after the decimal point are correct.

I'm a little confused on how to approach this. I think the constant C is really messing me up. Help please

share|cite|improve this question
Duplication. Same question also asked here:… – Graham Kemp Apr 30 '14 at 10:29

You want to find $c$ such that $P(X < c) = 0.95$, where $X$ is an exponential random variable with mean $1$ (as it is if the defendant is an innocent man: it doesn't say what the judge would do if the defendant were a woman).

share|cite|improve this answer

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.