What is the convention for denoting functions of two variables in statistics?

[Legendre]

Homework Statement

Quick question...

I have seen both being used : f(x,a) and f(x;a). What is the usual convention? Are both acceptable to denote functions of 2 variables (in this case f is a function of both x and a). Or are there vital differences between the two that I don't know about?

Thanks! :)

Homework Equations

N.A.

The Attempt at a Solution

N.A.

 

[Mark44]

I don't recall ever seeing this notation -- f(x; a) -- being used.

 

[statdad]

notation like f(x;a) is used in mathematical statistics when you want to show that a distribution depends on a parameter (real or vector-valued). for example, if you are talking about a normal distribution with some mean and standard deviation, writing
\theta = (\mu, \sigma) the density would be indicated f(x;\theta)

it indicates that the function depends on x and involves a parameter \theta (so, as we say in statistics, by varying \theta we obtain not one but a family of normal distributions.