manually calculating a linear regression

[Matthew]

I don't currently have access to the predictive tool suite.

So I'm trying to fit a linear regression to a data set using the formula tool, but i'm doing something wrong, is anyone familiar with the math behind linear regressions?

here is a plot of the input data

Here is a plot of the output.. the scale is waaayyy off, but i don't understand why

[Matthew · Accepted solution]

i found the solution.. i also may have rewritten the slope and intercept formulas.. but ultimately the problem was with the way i was numbering the rows.. as soon as there were multiple groups, the RecordID tool wouldnt do the job anymore, so i switched to the Tile tool

so i now have a working linear regression tool