Regression Formulas

The following formulas are used for linear regression. For geometrical regression, replace x and y with ln x and ln y. For exponential regression replace y only, and for logarithmic regression replace x only.

Formulas:

    a = (Σy - b·Σx) / n
    b = (n·Σxy - Σx·Σy) / (n·Σx² - Σx·Σx) 

Coeff. of determination  r² = h1 / h2

Coeff. of correlation       r  = √r²

Variance                        s² = (h2 - h1) / (n-2)

Standard deviation        s  = √s²

with  h1 = b·(Σxy - 1/n·Σx·Σy)  and   h2 = Σy² - 1/n·Σy·Σy