The probability that a student takes an English class and a math class is 0.084. The probability that a student takes an English class is 0.49. What is the probability that a student takes a math class given that the student is taking an English class?

Question

anonymous · Answer

@mathmale

mathmale · Answer

this is a case of conditional probability.  Have you solved conditional probability problems before?

anonymous · Answer

yes but i have hard time solving these questions @mathmale

mathmale · Answer

I am just retired and no longer have my statistics textbooks around for reference.  I'd like for you to look through your book, if you have one, for "conditional probability," and find a suitable equation there.  In the meantime I will search the Internet for such an equation.

anonymous · Answer

oh ok i will

mathmale · Answer

Any luck yet? Try http://www.stat.yale.edu/Courses/1997-98/101/condprob.htm

mathmale · Answer

The prominently featured formula at the top of this document is the one we need to solve this probability problem.

anonymous · Answer

@mathmale how do i solve it?

mathmale · Answer

Would you mind copying down that formula and trying to adapt it to the problem at hand?

Could you try something and share the results with me?  I'll be back with you shortly.

anonymous · Answer

0.717 @mathmale

mathmale · Answer

thanks.  Next time, please also show how you arrived at your result.  give me just a moment, please, while i try the problem myself.

anonymous · Answer

@mathmale lol ur out of moments :p

mathmale · Answer

Oh, you have to sign off your OpenStudy account?  Very sorry.

anonymous · Answer

lol im confused.

mathmale · Answer

I'll be right with you.  I'm reviewing the problem and the formula and will work it through myself.

mathmale · Answer

The probability that a student takes an English class and a math class is 0.084. The probability that a student takes an English class is 0.49. What is the probability that a student takes a math class given that the student is taking an English class? the formula for conditional probability is that given at the top of the page at http://www.stat.yale.edu/Courses/1997-98/101/condprob.htm. P(A AND B) P(B|A) = ----------- P(A) Adapting that to the problem y ou've posted, P(M AND E) P(M|E) = ------------ P(M) Please substitute the given probability values and see what you come up with . Perhaps you've alreasdy done this: didn't you suggest that the answer was 0.717?

mathmale · Answer

I got (0.084 / 0.49) = 0.171.  You're very close!
you decide for yourself wehther you're satsified or not; if not, ask further questions and I'll see what I can do.

mathmale · Answer

So:  you feeling good about this solution?  Hope so.  many thanks for the medal.

anonymous · Answer

np and Thank You

mathmale · Answer

You're very welcome!