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

1. Nov 30, 2005

### littlerich

Normal Distribution: Mean = 3, Variance = 16

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

Find c.

I'm so stuck...

Rich

2. Nov 30, 2005

### Hurkyl

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

Secondly, we're not here to do your homework for you. (See the guidelines) 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?

3. Nov 30, 2005

### littlerich

Hey

Yea, thats 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 im stuck.