Dear R-helpers,

I was curious why the output of summary (and many other functions in  
R) does not add a separator between the name of a factor and the label  
of a level (e.g., in the example below, 'group Trt'). If the user had  
lower case labels (e.g., 'trt'), the output would be particularly hard  
to read.
ctl <- c(4.17,5.58,5.18,6.11,4.50,4.61,5.17,4.53,5.33,5.14)
trt <- c(4.81,4.17,4.41,3.59,5.87,3.83,6.03,4.89,4.32,4.69)
group <- gl(2,10,20, labels=c("Ctl","Trt"))
weight <- c(ctl, trt)
summary(lm.D9 <- lm(weight ~ group))
gives
Call:
lm(formula = weight ~ group)

Residuals:
     Min      1Q  Median      3Q     Max
-1.0710 -0.4938  0.0685  0.2462  1.3690

Coefficients:
             Estimate Std. Error t value Pr(>|t|)
(Intercept)   5.0320     0.2202  22.850 9.55e-15 ***
groupTrt     -0.3710     0.3114  -1.191    0.249
---
Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1

Residual standard error: 0.6964 on 18 degrees of freedom
Multiple R-squared: 0.07308,	Adjusted R-squared: 0.02158
F-statistic: 1.419 on 1 and 18 DF,  p-value: 0.249
Why not"group Trt"?
_____________________________
Professor Michael Kubovy
University of Virginia
Department of Psychology
USPS:     P.O.Box 400400    Charlottesville, VA 22904-4400
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         McCormick Road    Charlottesville, VA 22903
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WWW:    http://www.people.virginia.edu/~mk9y/





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