The IMSL[7] routine DRONE
is used for the linear least squares fit and for the fit through the
origin ; DRPOLY is
used for the polynomial fits ; and
DRNLIN is used for the nonlinear
fits . The equation of the fit, the
correlation coefficient, the mean square residual over the variance,
the variance, and the number of points in the fit are shown. The
ANOVA table is available by entering `A` before a linear
or polynomial fit.

After selecting the nonlinear fit (with `
N`) you will be prompted for an expression and estimates for the
coefficients. For example, suppose you have just plotted
TAUP vs TE and you want to fit it to *a exp*^{-Te/b} + *c Te*,
you would enter the expression `a1*exp(-x/a2)+a3*x`. *A*1, *a*2,
and *a*3 are the coefficients for which you will be prompted for
estimates, and *x* refers to your *x* axis parameter or expression,
TE. *Note: Use x in the fit expression as shown, not
your x expression!* You can have up to 9 coefficients. The
nonlinear option can also be used to draw an arbitrary function of

If you have specified an error parameter for *y* then the estimate of
the error will be used in the fit. The linear and polynomial fits are
given for logarithmic axes as well as linear. You can write the
coefficients of a fit as well as the associated statistics to a file.
Prior to the graph, select the *write coefficients* option from
the OUTPUT submenu of PLOT.

Fri Jul 11 17:05:56 EDT 1997