Formulas in Forms, Expression Builder?

[summer]

I am trying to set up some formulas in a form I have created. I need to do a formula for standard deviation. I've been trying to use the expression builder, but it's confusing. I've selected StdDev, but I'm not sure how to enter my info. Can anyone help and show me examples?

 

[llkhoutx]

Maybe you can use a query for your record source. Queries have StdDev as a grouping method.