[R] Doubt about aov and lm function... bug?

Jose Claudio Faria joseclaudio.faria at gmail.com
Wed Apr 8 22:16:08 CEST 2009


Hi,

The below very strange:

#  a) aov function
av <- aov(Sepal.Length ~ Species, data=iris)

#  Error in parse(text = x) :
#   unexpected symbol in "Sepal(Sepal.Length+Species)Length"

av <- aov(iris[, 1] ~ iris[, 5])
#  summary(av)
#               Df Sum Sq Mean Sq F value Pr(>F)
#  iris[, 5]     2   63.2    31.6     119 <2e-16 ***
#  Residuals   147   39.0     0.3
#  ---
#  Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1



#  b) lm function
lm1 <- lm(Sepal.Length ~ Sepal.Width, data=iris)

#  Error in parse(text = x) :
#   unexpected symbol in "Sepal(Sepal.Length+Sepal.Width)Length"

lm1 <- lm(iris[, 1] ~ iris[, 2])
summary(lm1)

#  Call:
#  lm(formula = iris[, 1] ~ iris[, 2])
#
#  Residuals:
#     Min     1Q Median     3Q    Max
#  -1.556 -0.633 -0.112  0.558  2.223
#
#  Coefficients:
#              Estimate Std. Error t value Pr(>|t|)
#  (Intercept)    6.526      0.479   13.63   <2e-16 ***
#  iris[, 2]     -0.223      0.155   -1.44     0.15
#  ---
#  Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
#
#  Residual standard error: 0.82 on 148 degrees of freedom
#  Multiple R-squared: 0.0138,	Adjusted R-squared: 0.00716
#  F-statistic: 2.07 on 1 and 148 DF,  p-value: 0.152

I'm wrong or is it a bug?

platform       i386-pc-mingw32
arch           i386
os             mingw32
system         i386, mingw32
status         Patched
major          2
minor          8.1
year           2009
month          01
day            22
svn rev        47680
language       R
version.string R version 2.8.1 Patched (2009-01-22 r47680)

Thanks,
-- 
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Jose Claudio Faria
Estatistica - prof. Titular
UESC/DCET/Brasil
joseclaudio.faria at gmail.com
joseclaudio.faria at terra.com.br
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