Segmented Trendline

[Phil Hageman]

On a single series, is there a way to put multiple
trendlines on a series? Example: say data from January
throuth June are a positive slope, then from July through
December the slope is negative. Can I have separate
trendlines for each period?

Thanks,Phil

 

[Jon Peltier]

Phil -

You can have only one trendline per series, and the trendline analyzes
the entire series. You have two options, and both require breaking up
the data somehow.

Option 1 is to chart Jan-June as one series, and July-Dec as another,
and run separate trendlines.

Option 2 is to keep the series intact, but in your worksheet perform
linear regression (look up LINEST, or SLOPE and INTERCEPT if it's a
simple first order line fit), then use the parameters to determine the
X,Y pairs at either end of the fitted line segments, and plot these as
separate series.

The first option os probably easier.

- Jon