The continuous random variable Y is normally distributed with mean 15 and standard deviation 6

(a) Find P(X21)

(b) Find the value of d such that P(15<X<d)=0.3152

How do you answer part (b)?

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- March 12th 2010, 02:23 PMCSG18Finding an unknown value in normal distribution.
The continuous random variable Y is normally distributed with mean 15 and standard deviation 6

(a) Find P(X21)

(b) Find the value of d such that P(15<X<d)=0.3152

How do you answer part (b)? - March 12th 2010, 02:27 PMmr fantastic
- March 12th 2010, 02:32 PMCSG18
I do not understand where 0.5 comes from. Could you explain please? Also how would you reach the final answer..I guess I do not know how to solve a simple inverse normal problem..

Thanks! - March 12th 2010, 02:34 PMmr fantastic
- March 12th 2010, 02:49 PMCSG18
Well our teacher has not taught us normal distribution, so I have to learn it by myself. It's ok I'll figure it out.

Thanks - March 12th 2010, 02:52 PMmr fantastic
- March 12th 2010, 02:59 PMCSG18
It's going to be on my exam, but I don't think my teacher will have time to teach us it. So I will have to learn it.

Thanks I get it now! - March 12th 2010, 03:22 PMmr fantastic
How can an exam possbly test you on material that has not been taught? Unfortunately, there are many things the question you posted expects you to already understand. MHF cannot act as a surrogate teacher. If you have resolved to self-learn the normal distribution I suggest you obtain a decent textbook that covers the material and start from the very beginning.

I also suggest you discuss the issues raised in this thread with your teacher. - March 12th 2010, 05:56 PMCSG18
I understand, thanks for your help. I'm doing the IB and in my first year my original maths teacher was supposed to teach my class normal distribution but didn't, so now my new teacher probably won't have time to teach it.

- March 12th 2010, 10:45 PMmr fantastic