I have some data with two categorises plus/minus (p53) and a particular time (Time) and the outcome is a continuous vairable (Result). I set up a maximum model. ancova <- lm(Result~Time*p53) > summary(ancova) .. Coefficients: Estimate Std. Error t value Pr(>|t|) (Intercept) 0.05919 0.55646 0.106 0.916 Time -0.02134 0.01785 -1.195 0.241 p53plus 0.17059 0.78696 0.217 0.830 Time:p53plus 0.11887 0.02524 4.709 4.62e-05 *** ..
>From a plot of the data and the result of the linear model it looks like the two categories share the same intercept. How do I define this? I tried this: > ancova2<-update(ancova,~.-1) > summary(ancova2) Call: lm(formula = Result ~ Time + p53 + Time:p53 - 1) .. Coefficients: Estimate Std. Error t value Pr(>|t|) Time -0.02134 0.01785 -1.195 0.241 p53minus 0.05919 0.55646 0.106 0.916 p53plus 0.22977 0.55646 0.413 0.682 Time:p53plus 0.11887 0.02524 4.709 4.62e-05 *** But I do not think that is doing what I want. Many thanks -- ************************************************************** Daniel Brewer, Ph.D. Institute of Cancer Research Molecular Carcinogenesis Email: [EMAIL PROTECTED] ************************************************************** The Institute of Cancer Research: Royal Cancer Hospital, a charitable Company Limited by Guarantee, Registered in England under Company No. 534147 with its Registered Office at 123 Old Brompton Road, London SW7 3RP. This e-mail message is confidential and for use by the a...{{dropped:2}} ______________________________________________ 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.