SumSquaredErrors Command

SumSquaredErrors[ <List of Points>, <Function> ]

Calculates the sum of squared errors, SSE, between the y-values of the points in the list and the function values of the x-values in the list.

Example: If we have a list of points: L={A,B,C,D,E} and have calculated for example: f(x)=FitPoly[L,1] and g(x)=FitPoly[L,2], then it is possible to decide which of the two functions offers the best fit, in the sense of the least sum of squared errors (Gauss), by comparing: sse_f=SumSquaredErrors[L,f] and sse_g=SumSquaredErrors[L,g].