How do I create and save a new function in Excel?

[Sandals]

I want to create a new function for calculating standard error of a column of
data that I can enter in a cell and adjust for selecting the data to work
on. I just can't seem to find a way to save it as a new formula in the
function drop-down menu that I can use in future in different worksheets.
Just as one would enter a formula into a cell such as
=average(number1:number2) or =stdev(number1:number2) I want to be able to
enter =se(number1:number2) and it'll have the formula
=stdev(number1:number2)/sqrt(count(number1:number2)) as a stored excel
function that I don't have to write out in full everytime. Anyone got a
suggestion?

 

[Gary''s Student]

Consider using Visual Basic to create User Defined Functions.