Regression Formulas

The following formula are used for linear regression. In case of geometrical regression, x and y have to be substituted by ln x and ln y. In case of exponential regression only y, and in case of logarithmic regression only x has to be substituted.

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