Gets the value of the Chi-Squared measure of goodness-of-fit.
The value of Chi-Squared for the function of best fit.
The Chi-Square is a convenient measure of how well (globally) over the range considered the function of best fit, fits the data considered. Note that before the Chi-Squares can be evaluated the set function must first be fitted using SetGeneralFit.
Remark: Roughly speaking for an unweighted function of best fit, the square root of the Chi-Squared measure is the average distance in the y-direction from a data point to the curve of best fit.
Recall that here we are finding the curve of best fit in accordance with minimizing the sum of the squares of the terms:
( yi - (a1 * f1(xi) + ... + an * fn(xi)) / sigmai,
where we sum over the i, for 1 <= i <= n; the (xi, yi)
are the data points, f1,...,fn are the function basis elements and sigmai are
the standard deviations of the measurement error of the values of yi. The Chi-Squared measure
is precisely the value of this sum.
Please note that before this method is called you must have already performed the following tasks:
GeneralLinear Class | WebCab.COM.Statistics.CurveFitting Namespace