# Thread: Finding pdfs related to the standard normal

1. ## Finding pdfs related to the standard normal

Given a random variable Z is standard normal. I am trying to find the pdfs for the abs(Z) and Z^2.

I thought to start the abs(Z) by splitting the CDF of Z into two separate integrals and adding them (One for when Z>0 and one for when Z<0). Then I would take the derivative to get back to a pdf, but i am struggling to choose the limits of integration.

2. I just did the absolute value two days ago on this site.
see http://www.mathhelpforum.com/math-he...-function.html
the square can be found in many places, including in older threads at this forum
but the technique is very similar to the absolute value problem

3. Thank you. So for the absolute value of a random variable with a standard normal pdf, I got twice the standard normal pdf. And for the squared version I ended with 1/sqrt(2pix)*exp((-1/2)x).

4. what's pix?
pi times x?
ALSO, note that the domain in both case are zero to infinity.

5. Yes it's pi times x. Sorry, as an aside, a link to software to help write math notation would be helpful as well. I'm not sure I see how the domain helps.

6. Originally Posted by jass10816
Yes it's pi times x. Sorry, as an aside, a link to software to help write math notation would be helpful as well. I'm not sure I see how the domain helps.
hit the QUOTE link, from that you can see how people type the math in TeX.