xmp13.09 {Devore5} | R Documentation |
The xmp13.09
data frame has 8 rows and 2 columns of data on
cure temperature and ultimate sheer strength of rubber compounds.
This data frame contains the following columns:
Devore, J. L. (2003) Probability and Statistics for Engineering and the Sciences (6th ed), Duxbury
(1971), "A method for improving the accuracy of polynomial regression analysis", J. Quality Technology, 149–155.
data(xmp13.09) plot(strength ~ tempture, data = xmp13.09) fm1 <- lm(strength ~ tempture + I(tempture^2), data = xmp13.09) summary(fm1) xmp13.09$Tcentered <- scale(xmp13.09$tempture, scale = FALSE) fm2 <- lm(strength ~ Tcentered + I(Tcentered^2), data = xmp13.09) summary(fm2) ## another approach using orthogonal polynomials fm3 <- lm(strength ~ poly(tempture, 2), data = xmp13.09) summary(fm3)