# [R] ANOVA in R

Jim Lemon drj|m|emon @end|ng |rom gm@||@com
Thu Oct 11 00:25:17 CEST 2018

```Hi again,
Two things, I named the data frame SR as shown in the model.
The other is for those who may wish to answer the OP. The mediafire

Jim
On Thu, Oct 11, 2018 at 9:02 AM Jim Lemon <drjimlemon using gmail.com> wrote:
>
> Hi Tranh,
> I'm not sure why you are converting your variables to factors, and I
> think the model you want is:
>
> lm(KIC~temperature+AC+AV+Thickness+temperature:AC+
>  temperature:AV+temperature:thickness+AC:AV+
>  AC:thickness+AV:thickness,SR)
>
> Note the colons (:) rather than asterisks (*) for the interactions.
>
> Jim
> On Wed, Oct 10, 2018 at 5:14 PM Thanh Tran <masternhattt using 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.
> > 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
> > function in R to check for "orthogonal" designs. If not, use "adjusted sums
> > 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]]
> >
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