Calculate trend line

[Joe]

I need to add a trend line to a scatter plot (not automatically supported by
the charting package) but I don't know how to calculate it. Is there any
formulas around for calculating what the trend line should look like?

 

[Tyron Madlener]

I need to add a trend line to a scatter plot (not automatically supported by
the charting package) but I don't know how to calculate it. Is there any
formulas around for calculating what the trend line should look like?

http://en.wikipedia.org/wiki/Linear_regression

 

[Joe]

Thanks but I was looking for an actual function or library. Since I'm not a
math major this is going to take a while to figure out.