Add a custom title, specify prior parameter values, or specify weights.
In Title, enter your own custom title to replace the default title.
A weighted trend analysis includes fitting the same trend model to previous data in order to obtain an improved fit to the current data. The smoothed trend line combines the previous estimates and the new estimates in much the same way as exponential smoothing. This smoothing of the parameter estimates filters out some of the noise from the estimates in successive cycles.
If you supply estimates from a previous trend analysis fit, Minitab does a weighted trend analysis. If the weight for a specific estimate is α, Minitab estimates the new parameter by:
α p1 + (1 - α) p2 , where p1 is the parameter estimated from the current data and p2 is the prior estimate.
Minitab generates a time series plot of the data, and a second time series plot that shows trend lines for three models. The Session window displays the parameters and accuracy measures for all three models.