geepeetee wrote:
Hi

Thanks, that worked a treat. Just one last thing, we need a "line of best
fit" which a straight line which goes through as many points a possible.

I have drawn this on and its fine but wondered if there is a way of letting
the software do it.

Cheers
Gary
"geepeetee" wrote in message
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At risk of nit picking -- a line of best fit does not go through as many
points as possible. It is a line which minimizes an error function of
some kind. Most commonly it is an LSQ line -- a "Least Squares" fit.
You square the error at each data point, sum all the errors and try to
minimize that function with the generated line. It may well not
actually go through a single point even.

Bill