# Finding a cumulative distribution function for a random variable x

• Oct 14th 2010, 07:36 AM
bbob37
Finding a cumulative distribution function for a random variable x
I understand how to find a CDF of a function given f(x) and appropriate intervals, but this questions throws me off.

Find the C.D.F. for the following random variables:

a.) Let X be exponential with parameter lambda.

There are other facets to this question, but I should be able to answer them after understanding part a.
• Oct 14th 2010, 04:01 PM
yannyy
$\displaystyle f(x)=\lambda e^{-\lambda x}$
integrate this from 0 to x to get the C.D.F
• Oct 14th 2010, 04:02 PM
mr fantastic
Quote:

Originally Posted by bbob37
I understand how to find a CDF of a function given f(x) and appropriate intervals, but this questions throws me off.

Find the C.D.F. for the following random variables:

a.) Let X be exponential with parameter lambda.

There are other facets to this question, but I should be able to answer them after understanding part a.

I don't see where the problem is. You know what the pdf is (look it up if you need to). And you know the definition of cdf, right? So, where are you stuck?