[R] details about lm()

[Uwe Ligges]

vincent at 7d4.com wrote:

> Domenico Cozzetto a écrit :
> 
> 
>>Dear all,
>>I'd like to get a linear regression of some data, and impose that the line
>>goes through a given point P. I've tried to use the lm() method in the
>>package "stats", but I wasn't able to specify the coordinates of the point
>>P. Maybe I should use another method?
> 
> 
> add directly P in your data is also a way

No!

Please, both of you, consult a basic textbook on linear regression.

You can transform the data (linear) so that P becomes (0,0), after that 
  you can estimate the slope without intercept by specifying
  lm(y ~ x - 1)
The slope estimate is still valid while your intercept can be calculated 
afterwards.

Uwe Ligges


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