Help Calculating Likely Range of ROI

[ThorGoT]

Assume I have a 25% ROI over 500 games (or, perhaps, a 24.34% ROI over 516 games). I know there is a formula for calculating what my real ROI is (with 95% and 65% certainty, or something like that). But I can't seem to locate it using the search function. Plus my math/statistical background is weak. I remember what a square root is, though. Can anyone help? Thanks

[AleoMagus]

This thread has all the math

Confidence Calculations (http://forumserver.twoplustwo.com/favlinker.php?Cat=&Entry=54096&F_Board=singletable &Thread=1373360&partnumber=&postmarker=)

but if you want to avoid doing all that, you can just download one of the many spreadsheets floating around. They all calculate confidence. (the penultimate sheet is currently near the top of the forum but has a few bugs still)

or, you could just download the confidence calculator that was eventually incorporated into those sheets

Confidence calculator (http://www.aleomagus.freeservers.com/Spreadsheet)

it is the confidence calculator file.

Regards
Brad S