You can get the name of var by doing coeffname <- deparse(substitute(var))
Is that what you wanted? -- Gregory (Greg) L. Snow Ph.D. Statistical Data Center Intermountain Healthcare greg.s...@imail.org 801.408.8111 > -----Original Message----- > From: r-help-boun...@r-project.org [mailto:r-help-boun...@r- > project.org] On Behalf Of Jan private > Sent: Saturday, October 16, 2010 9:41 PM > To: r-help > Subject: [R] Variable name as string > > Hello, > > from Verzani, simpleR (pdf), p. 80, I created the following function to > test the coefficient of lm() against an arbitrary value. > > coeff.test <- function(lm.result, var, coeffname, value) { > # null hypothesis: coeff = value > # alternative hypothesis: coeff != value > es <- resid(lm.result) > coeff <- (coefficients(lm.result))[[coeffname]] > # degrees of freedom = length(var) - number of coefficients? > n <- df.residual(lm.result) > s <- sqrt( sum( es^2 ) / n ) > SE <- s/sqrt(sum((var - mean(var))^2)) > t <- (coeff - value )/SE > 2 * pt(t,n,lower.tail=FALSE) # times two because problem is two-sided > } > > E.g. it needs to be called coeff.test(lm(N ~ D), D, "D", 70) if I want > to test the probability slope of the linear model being 70. > > Is there a more elegant way to avoid passing D and "D" both as > parameters? > > Also, as a non-professional, I would like to know whether the function > is valid for all coefficients of lm(), e.g. coeff.test(lm(N ~ D + H), > H, > "H", 70). I am aware that Verzani gives a different formula for testing > the intercept. > > Thanks! > Jan Rheinländer > > ______________________________________________ > 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. ______________________________________________ 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.
