Question about linear regression in R
On Nov 14, 2011, at 10:49 PM, Miles Yang wrote:
Hi all, I wrote a r program as below: x <- 1:10 y <- c(3,3,3,3,3,3,3,3,3,3) fit <- lm(log(y) ~ x) summary(fit) And I expect to get some error message from R, because "y" is constant. But, I got the message as below:
You are asking R to tell you if the mean of the log of 3 was different than 0. It is.
David. > >> summary(fit) > > Call: > lm(formula = log(y) ~ x) > > Residuals: > Min 1Q Median 3Q Max > -6.802e-17 -3.933e-17 -1.063e-17 1.807e-17 1.530e-16 > > Coefficients: > Estimate Std. Error t value Pr(>|t|) > (Intercept) 1.099e+00 4.569e-17 2.404e+16 <2e-16 *** > x -1.275e-17 7.364e-18 -1.732e+00 0.122 > --- > Signif. codes: 0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1 > > Residual standard error: 6.688e-17 on 8 degrees of freedom > Multiple R-squared: 0.5794, Adjusted R-squared: 0.5269 > F-statistic: 11.02 on 1 and 8 DF, p-value: 0.01054 > > How could this be possible? > Did I missing something in my R code? > > Best, > Miles > -- > ?????????????????? > Miles Yang > Mobile?+61-411-985-538 > E-mail?miles2yang at gmail.com > ?????????????????? > > [[alternative HTML version deleted]] > > ______________________________________________ > R-help at 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. David Winsemius, MD West Hartford, CT