Hand Fitting Trend Of Forecasting
A hand fit or freehand curve is simply a plot of a representative line that (subjectively) seems to best fit the data points. For linear data, the forecasting equation will be of the form:
Yc = a + b (X) (signature)
where Yc is the trend value, a is the intercept (where line crosses the vertical axis), b is the slope (the rise, Dy, divided by the run, Dx), and X is the time value (years, quarters, etc.). The “signature” identifies the point in time when X = 0, as well as the X and Y units.