How do you calulate "C.V." (Coefficient of Variation) AT (<this is important) 90% confidence?

Typically, to calculate "C.V.", you divide the standard deviation by the mean...but I need to calculate "C.V." AT 90% confidence?!

How do you calulate "C.V." (Coefficient of Variation) AT (%26lt;this is important) 90% confidence?
If you give me the information you have, i might be able to figure it out for you. It's important to know the distribution so I can lead you in the right direction. If you made an edit... i'll check back.

cabbage