wt

Usage: wt [none stat inst other]

The fitting function tries to minimize χ2, where χ2 = $\sum$((yi-f (xi))/σi)2. That is, χ2 is the sum of the squared error of the difference between the data and the fitting function, except that each term in the sum is weighted by σi2. The wt command chooses the type of weighting. It chooses what to use for σ. Errors in the independent parameters can also be used for non-linear fitting. See the order command for details. The following weighting options are available:

none..........no weighting, all σ's are equal to one.

statistical... σi = $\sqrt{{y_i}}$

instrumental.. σi = δyi, as in data file

other......... σi = yi

Example: wt s selects statistical weighting.