Hi Anne, I would suggest to change the linear model to lm(BloodPressure~Age), as this model makes more sense in biological means (you would assume that age influences pressure, not vice versa) and also obeys the statistical assumption of weak exogeneity, that age can be measured without error, at least compared to error-prone bp measures.
Cheers Am 18.04.2018 um 16:07 schrieb Gerrit Eichner: > Hi, Anne, > > assign Age and Bloodpressure in the correct order > to the axes in your call to plot as in: > > plot(y = Age, x = BloodPressure) > abline(SimpleLinearReg1) > > > Hth -- Gerrit > > --------------------------------------------------------------------- > Dr. Gerrit Eichner Mathematical Institute, Room 212 > gerrit.eich...@math.uni-giessen.de Justus-Liebig-University Giessen > Tel: +49-(0)641-99-32104 Arndtstr. 2, 35392 Giessen, Germany > http://www.uni-giessen.de/eichner > --------------------------------------------------------------------- > > > Am 18.04.2018 um 15:26 schrieb CHATTON Anne via R-help: >> Hello, >> >> I am trying to graph a regression line using the followings: >> >> Age <- c(39, 47, 45, 47, 65, 46, 67, 42, 67, 56, 64, 56, 59, 34, 42, >> 48, 45, >> 17, 20, 19, 36, 50, 39, 21, 44, 53, 63, 29, 25, 69) >> BloodPressure <- c(144, 220, 138, 145, 162, 142, 170, 124, 158, 154, 162, >> 150, 140, 110, 128, 130, 135, 114, 116, 124, 136, 142, 120, 120, 160, >> 158, >> 144, 130, 125, 175) >> SimpleLinearReg1=lm(Age ~ BloodPressure) >> summary(SimpleLinearReg1) >> eq = paste0("y = ", round(coeff[2],1), "*x ", round(coeff[1],1)) >> plot(Age, BloodPressure, pch = 16, cex = 1.3, col = "blue", >> main = eq, xlab = "Age (Year)", ylab = "Blood Pressure (mmHg)") >> abline(SimpleLinearReg1, col="red") >> mean(Age) >> mean(BloodPressure) >> abline(h=142.53, col="green") >> abline(v=45.13, col="green") >> >> But I cannot get the regression line. Can anybody tell me what's wrong >> with the codes ? I would appreciate very much. Thanks for any help. >> >> Anne >> >> [[alternative HTML version deleted]] >> >> ______________________________________________ >> R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see >> 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. >> > > -- Eik Vettorazzi Department of Medical Biometry and Epidemiology University Medical Center Hamburg-Eppendorf Martinistrasse 52 building W 34 20246 Hamburg Phone: +49 (0) 40 7410 - 58243 Fax: +49 (0) 40 7410 - 57790 Web: www.uke.de/imbe -- _____________________________________________________________________ Universitätsklinikum Hamburg-Eppendorf; Körperschaft des öffentlichen Rechts; Gerichtsstand: Hamburg | www.uke.de Vorstandsmitglieder: Prof. Dr. Burkhard Göke (Vorsitzender), Prof. Dr. Dr. Uwe Koch-Gromus, Joachim Prölß, Martina Saurin (komm.) _____________________________________________________________________ SAVE PAPER - THINK BEFORE PRINTING ______________________________________________ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see 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.
