Sum or average of user eval_score

[jwood29]

I have an Admin form that I need help with getting sum and/or average from two different tables. How would I go about getting a text box to display Sum or average of users evalution scores.

Table: User
user_name

Table: Evaluation
eval_score


Table: Admin
Form: user_name combo
eval_score button (display avg of User X eval score) ?

Thanks.