[ThunderSleeps]

Sorry, I should have been more specific. To me a "modest number" of data points is several hundred, maybe a thousand. (I routinely deal with data sets in the tens of thousands, pushing 7 figures)

In the case of a hundred or so data points, for any reasonably self-consistent data set (eg. surface temperature) that isn't likely to see wild data points then any one does not have much of a chance of drastically influencing slope of the line.

[The_Reader_David]

Here are Briggs's realistic time-series examples: and taken from here.