Probability!

[behappy87]

What's the difference between a probability mass function and a probability density function? I really should know this, but I just can't see the difference! Thanks.

[Peter Pedant]

erm erm - if a pdf is f(x)
then isnt f1(x) the mean,
and F2(x) the standard deviation ?

and this isnt a property of the pmf ?

At wairch at this time, but when i get home, I know a book, etc etc

[Peter Pedant]

yeah got to the book
and it only has pdf's
sorry