HP 35s Scientific Calculator - Manual (Page 248)

16-2 Statistics Programs
To fit logarithmic curves, values of x must be positive. To fit exponential curves,
values of y must be positive. To fit power curves, both x and y must be positive. A
 error will occur if a negative number is entered for these cases.
Data values of large magnitude but relatively small differences can incur problems
of precision, as can data values of greatly different magnitudes. Refer to "Limitations
in Precision of Data" in chapter 12.
y
x
y B Mx = +
Straight Line Fit
S
y
x
y Be
Mx
=
Exponential Curve Fit
E
y
x
y B MIn x = +
Logarithmic Curve Fit
L
y
x
y BxM =
Power Curve Fit
P