Linear fit

The curve calculation is based on the least squares fit (see Calibration curve calculation).

Curve formula:

y = a * x + b

where
a	Slope
b	Y-intercept

Calculation of curve coefficients:

At least two calibration points are required for a linear fit.

Include origin

If the origin is included, the point (0,0) is added to the other points and weighted by the mean value of the weights of the other points, that is, the Σ(wt) term is increased by the mean value of the weights of the other points.

Force origin

If the force origin option is selected the curve formula is as follows:

y = a * x

where
a	Slope

Calculation of curve coefficient:

Only one calibration level is required when the origin is included or forced.