Norm Loomer wrote:
>
> A colleague brought me some annual time series data that shows a
> downward trend from 1992 to 2001. In 1996 the agency that recorded the
> data adopted a new program that, if successful, would cause the data to
> trend downward more sharply. What they are looking for, I think, is
> evidence that the slope after 1996 is greater (in absolute value) than
> the slope before 1996. Can someone help me with this?
Probably not, unless the trend change is enormous or the random
variation miniscule. Fitting a three-degree-of-freedom model with ten
data is usually overfitting.
-Robert Dawson
.
.
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