The devil is in the details, and you've left out one important detail:
what are you using for known_x? The intercept, of course, is the value
of y when x=0.

If I use "2007, 2008, 2009, 2010" for known_x, I get the same from
INTERCEPT as your worksheet got. In this case, known_x refers to
"years since 1 BC" (ie 1 BC is year 0).

If I use "1, 2, 3, 4" for known_x, I get the same from INTERCEPT as
your chart trendline gave. In this case, known_x refers to "years
since 2006" (ie 2006 is year 0).

As long as you're consistent in your use of independent variable,
neither is necessarily more correct than the other.


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MrShorty
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