# Math Help - quick and dumb question...

1. ## quick and dumb question...

To get the c.d.f. from a p.d.f. of a continuous random variable do I just integrate the p.d.f.?

2. Originally Posted by billym
To get the c.d.f. from a p.d.f. of a continuous random variable do I just integrate the p.d.f.?
yes, but pay attention to the bounds

$F(x)=P(X\le x)$

in any situation, and in the continuous case you have

$F(x)=P(X\le x)=\int_{-\infty}^x f(t)dt$

where we need a dummy variable of integration.