How Do You Solve for c in a Normal Distribution Problem?

[littlerich]

Normal Distribution: Mean = 3, Variance = 16

P(|X-2|>c)=0.6

Find c.

I'm so stuck...

Please Help Me

Rich

 

[Hurkyl]

First off, you should post homework in the homework forums.

Secondly, we're not here to do your homework for you. (See https://www.physicsforums.com/showthread.php?t=94383) You have to show us what you've tried on the problem, even if you think it is going nowhere! (e.g. it is almost always a good idea to try applying the definitions of things -- some of us get the feeling you haven't even bothered trying to do the problem if you haven't even done that!)

Finally, your post is a little confusing. I suppose you meant to say that X is a normally distributed random variable with mean 3 and variance 16?

 

[littlerich]

Hey

Yea, that's what i meant...

What I've tried so far is:

P(X>c+2)+P(X<2-c)=0.6

Hence: P(X<c+2)-P(X<2-c)=0.4

And because my tables are backwards i changed it to:

P(X>2-c)-P(X>c+2)=0.4

0.4 then comes up as 0.2533 in the tables, and now I am stuck.