R help - Oct 2002 - lm fitting with a specified slope

Is there an easy way to do a linear model with an a priori known slope?

In essence, I want to minimize the residuals around a line of known slope.

-R

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Assume the model:

  X1 <- rnorm(1000)
  X2 <- rnorm(1000)

  B1 = 1.75 # known a-priorori
  B2 = 0.5  # unknown a-priorori

  Y  <- 1.75 * X1 + 0.5 * X2  + rnorm(1000,sd=0.25)

Then wouldn't this do the trick? :

  reg <- lm( (Y - 1.75 * X1) ~ X2 ) 


-Greg
> -----Original Message-----
> From: Rob Lee [mailto:rlee at fpcc.net]
> Sent: Thursday, October 03, 2002 3:15 PM
> To: r-help at stat.math.ethz.ch
> Subject: [R] lm fitting with a specified slope 
> 
> 
> 
> Is there an easy way to do a linear model with an a priori 
> known slope?
> 
> In essence, I want to minimize the residuals around a line of 
> known slope.
> 
> -R
> 
> -.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.
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You want offset.

Kjetil Halvorsen

Rob Lee wrote:
> 
> Is there an easy way to do a linear model with an a priori known slope?
> 
> In essence, I want to minimize the residuals around a line of known slope.
> 
> -R
> 
>
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> r-help mailing list -- Read http://www.ci.tuwien.ac.at/~hornik/R/R-FAQ.html
> Send "info", "help", or "[un]subscribe"
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>
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