We cannot read your message. Should post pure text, not html. Hm, my phone now may post html, must try to stop. Your R code not legible. It seems to be output? Lines all run together. I tried find articles you mention, but "not found" resulted.
You should use aov() for fitting, then get post hoc comparisons. In car package, Anova function will help. I may teach Anova soon, we'll see if I have better answer then. Paul Johnson University of Kansas On Wed, Oct 10, 2018, 1:14 AM Thanh Tran <masternha...@gmail.com> wrote: > Hi eveyone, > I'm studying about variance (ANOVA) in R and have some questions to share. > I read an article investigating the effect of factors (temperature, Asphalt > content, Air voids, and sample thickness) on the hardness of asphalt > concrete in the tensile test (abbreviated as Kic). Each condition was > repeated four times (4 samples). In the paper, the authors used MINITAB to > analyze Anova. The authors use "adjusted sums of squares" calculate the > p-value I try to use ANOVA in R to analyze this data and get the result as > shown in Figure 4. The results are different from the results in the > article. Some papers say that in R, the default for ANOVA analysis is to > use "sequential sums of squares" to calculate the p-value. > So please help the following two questions: 1 / Introduction to code in R > for anova analysis uses "adjusted sums of squares". The main part of the > command in R / myself is as follows: > Tem = as.factor (temperature) > Ac = > as.factor (AC) > Av = as.factor (AV) > Thick = as.factor (Thickness) > > Twoway = lm (KIC ~ Tem + Ac + Av + Thick + Stamp + Ac + Stamp + Av + Stamp > + Thick + Ac * Av + Ac * Thick + Av * Thick) > anova (twoway) 2/ When to > use "sequential sums of squares" and when to use "adjusted sums of > squares". Some papers recommend using the "oa.design > < > https://www.youtube.com/redirect?q=http%3A%2F%2Foa.design%2F&redir_token=AaSAPDY-5UAsoHxN6BdwfyIJ7R98MTUzOTIxNDg2OUAxNTM5MTI4NDY5&event=comments > >" > function in R to check for "orthogonal" designs. If not, use "adjusted sums > of squares". I am still vague about this command, so look forward to > everyone's suggestion. If you could answer all two of my questions, I would > be most grateful. Ps: I have added a CSV file and the paper for practicing > R. http://www.mediafire.com/file/e5oe54p2c2wd4bc/Saha+research.csv > > http://www.mediafire.com/file/39jlf9h539y9mdz/Homothetic+behaviour+investigation+on+fracture+toughness+of+asphalt+mixtures+using+semicircular+bending+test.pdf > > [[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. > [[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.
