sql guy123 (st*****@hotmail.com) writes:
This is a real challenge. I hope someone is smart enough to know how
to do this.
I have a table
TABLE1
[Column 1- 2001]
[Column 2- 2002]
[Column 3- 2003]
[Column 4 - 2004]
[Column 5 - 2005]
[Column 6 - 2006]
[Column 7 - Slope]
[2001][2002][2003][2004][2005][2006] [Slope]
[1] [2] [3] [4] [5] [6] [1]
[1.2] [.9] [4] [5] [5.4] [6.2] [?]
Slope is defined as "M" in the equation y=mx+b
I need a way a finding the linear equation that best fits the points so
I can have SQL calculate the slope.
Are there any smart people around that would know how to do this?
Smart? Either you did learn linear regression in school or you didn't.
I will have to admit that although I taught mathematical statistics as a
student, that I've forgotten the forumulas. But I looked them up in my
statisticcs book:
m = SUM((Xi - AVG(X))*(Yi - AVG(Y)) / SUM(SQR(Xi - AVG(X))
where Xi and Yi are the individual values for the X and Y variables.
For the computation in SQL you can of course not use SUM and AVG since
your table is turned the wrong way. The years should have been columns
instead.
--
Erland Sommarskog, SQL Server MVP,
es****@sommarskog.se
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