Re: [R] Testing year effect in lm() ***failed first time, sending again

2009-08-06 Thread Emmanuel Charpentier
Le mercredi 05 août 2009 à 09:52 -0700, Mark Difford a écrit :
 Emmanuel,
 
  somewhat incomplete  help pages : what in h*ll are valid arguments to
  mcp() beyond Tukey ??? Curently, you'll have to dig in the source to
  learn that...).
 
 Not so: they are clearly stated in ?contrMat.

Oops.. I oversaw that.

With my apologies,

Emmanuel Charpentier

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Re: [R] Testing year effect in lm() ***failed first time, sending again

2009-08-05 Thread Emmanuel Charpentier
Le jeudi 30 juillet 2009 à 16:41 -0600, Mark Na a écrit :
 Dear R-helpers,
 
 I have a linear model with a year effect (year is coded as a factor), i.e.
 the parameter estimates for each level of my year variable have significant
 P values (see some output below) and I am interested in testing:
 
 a) the overall effect of year;
 b) the significance of each year vis-a-vis every other year (the model
 output only tests each year against the baseline year).

install.packges(multcomp)
help.start()

and use the vignettes ! They're good (and are a good complement to
somewhat incomplete  help pages : what in h*ll are valid arguments to
mcp() beyond Tukey ??? Curently, you'll have to dig in the source to
learn that...).

HTH

Emmanuel Charpentier

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Re: [R] Testing year effect in lm() ***failed first time, sending again

2009-08-05 Thread Mark Difford

Emmanuel,

 somewhat incomplete  help pages : what in h*ll are valid arguments to
 mcp() beyond Tukey ??? Curently, you'll have to dig in the source to
 learn that...).

Not so: they are clearly stated in ?contrMat.

Regards, Mark.


Emmanuel Charpentier-3 wrote:
 
 Le jeudi 30 juillet 2009 à 16:41 -0600, Mark Na a écrit :
 Dear R-helpers,
 
 I have a linear model with a year effect (year is coded as a factor),
 i.e.
 the parameter estimates for each level of my year variable have
 significant
 P values (see some output below) and I am interested in testing:
 
 a) the overall effect of year;
 b) the significance of each year vis-a-vis every other year (the model
 output only tests each year against the baseline year).
 
 install.packges(multcomp)
 help.start()
 
 and use the vignettes ! They're good (and are a good complement to
 somewhat incomplete  help pages : what in h*ll are valid arguments to
 mcp() beyond Tukey ??? Curently, you'll have to dig in the source to
 learn that...).
 
 HTH
 
   Emmanuel Charpentier
 
 __
 R-help@r-project.org mailing list
 https://stat.ethz.ch/mailman/listinfo/r-help
 PLEASE do read the posting guide
 http://www.R-project.org/posting-guide.html
 and provide commented, minimal, self-contained, reproducible code.
 
 

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[R] Testing year effect in lm() ***failed first time, sending again

2009-07-30 Thread Mark Na
Dear R-helpers,

I have a linear model with a year effect (year is coded as a factor), i.e.
the parameter estimates for each level of my year variable have significant
P values (see some output below) and I am interested in testing:

a) the overall effect of year;
b) the significance of each year vis-a-vis every other year (the model
output only tests each year against the baseline year).

I'd appreciate any help with how to perform these post-hoc tests in R.

Many thanks,

Mark Na



Call:

lm(formula = data$SR.obs ~ log(data$AREA, 10) + data$YEAR,

subset = (data$AREA = 14.5))



Residuals:

Min  1Q  Median  3Q Max

-5.3412 -1.3140  0.1108  1.1972  4.3126



Coefficients:

   Estimate Std. Error t value Pr(|t|)

(Intercept) -9.4606 0.6144 -15.399   2e-16 ***

log(data$AREA, 10)   3.9261 0.1734  22.644   2e-16 ***

data$YEAR20081.0750 0.2854   3.767 0.000211 ***

data$YEAR20091.5884 0.3073   5.169 5.18e-07 ***

---

Signif. codes:  0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1



Residual standard error: 1.822 on 226 degrees of freedom

Multiple R-squared: 0.6945, Adjusted R-squared: 0.6905

F-statistic: 171.3 on 3 and 226 DF,  p-value:  2.2e-16



[1] AIC=  934.557

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