# Expression for the variances

1. Sep 10, 2011

### 123infinity

1. The problem statement, all variables and given/known data

Determine the expression for the variances in x (that is $\sigma$2) with respect to the appropriate variables for the following:

a) X = $\frac{wy}{z}$, with variance in w,y,z

2. Relevant equations

I'm having trouble typing out the equation, but the equation I know for variance is here:
http://people.richland.edu/james/ictcm/2001/descriptive/helpvariance.html

Maybe I'm not thinking about this the right way, should I not be thinking about sample/population variance? So then I just tried thinking about what I'm trying to find.... Maybe I should be thinking about relating it to standard deviation to find it?