Hi Greg. Thanks for your reply. Do you know if there is a way to use the confint function to get a p-value on this test?
Thanks, Mark On Mon, Apr 23, 2012 at 3:10 PM, Greg Snow <538...@gmail.com> wrote: > One option is to subtract the continuous variable from y before doing > the regression (this works with any regression package/function). The > probably better way in R is to use the 'offset' function: > > formula = I(log(data$AB.obs + 1, 10)-log(data$SIZE,10)) ~ > log(data$SIZE, 10) + data$Y > formula = log(data$AB.obs + 1) ~ offset( log(data$SIZE,10) ) + > log(data$SIZE,10) + data$Y > > Or you can use a function like 'confint' to find the confidence > interval for the slope and see if 1 is in the interval. > > On Mon, Apr 23, 2012 at 12:11 PM, Mark Na <mtb...@gmail.com> wrote: > > Dear R-helpers, > > > > I would like to test if the slope corresponding to a continuous variable > in > > my model (summary below) is different than one. > > > > I would appreciate any ideas for how I could do this in R, after having > > specified and run this model? > > > > Many thanks, > > > > Mark Na > > > > > > > > Call: > > lm(formula = log(data$AB.obs + 1, 10) ~ log(data$SIZE, 10) + > > data$Y) > > > > Residuals: > > Min 1Q Median 3Q Max > > -0.94368 -0.13870 0.04398 0.17825 0.63365 > > > > Coefficients: > > Estimate Std. Error t value Pr(>|t|) > > (Intercept) -1.18282 0.09120 -12.970 < 2e-16 *** > > log(data$SIZE, 10) 0.56009 0.02564 21.846 < 2e-16 *** > > data$Y2008 0.16825 0.04366 3.854 0.000151 *** > > data$Y2009 0.20310 0.04707 4.315 0.0000238 *** > > --- > > Signif. codes: 0 *** 0.001 ** 0.01 * 0.05 . 0.1 1 > > > > Residual standard error: 0.2793 on 228 degrees of freedom > > Multiple R-squared: 0.6768, Adjusted R-squared: 0.6726 > > F-statistic: 159.2 on 3 and 228 DF, p-value: < 2.2e-16 > > > > [[alternative HTML version deleted]] > > > > > > ______________________________________________ > > 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. > > > > > > -- > Gregory (Greg) L. Snow Ph.D. > 538...@gmail.com > [[alternative HTML version deleted]]
______________________________________________ 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.
