Hello, I'm new to R and have been following many guides including the two-way
anova (http://www.personality-project.org/r/r.anova.html). Using that
walkthrough including the supplied data I do str(data.ex2) and receive the
appropriate types of data as follows:
> str(data.ex2)
'data.frame': 16 obs. of 4 variables:
$ Observation: int 1 2 3 4 5 6 7 8 9 10 ...
$ Gender : Factor w/ 2 levels "f","m": 2 2 2 2 2 2 2 2 1 1 ...
$ Dosage : Factor w/ 2 levels "a","b": 1 1 1 1 2 2 2 2 1 1 ...
$ Alertness : int 8 12 13 12 6 7 23 14 15 12 ...
aov.ex2 = aov(Alertness~Gender*Dosage,data=data.ex2)
summary(aov.ex2)
Outputs:
Df Sum Sq Mean Sq F value Pr(>F)
Gender 1 76.562 76.562 2.9518 0.1115
Dosage 1 5.062 5.062 0.1952 0.6665
Gender:Dosage 1 0.063 0.063 0.0024 0.9617
Residuals 12 311.250 25.938
However, when I got to use my data that I made in csv format I have to tell
R to interpret my factors which are year and depth as factors...
datafilename="C:/Rclass/hmwk1pt2.csv"
data.ex2=read.csv(datafilename,header=T)
data.ex2$Year<-as.factor(data.ex2$Year)
data.ex2$Depth<-as.factor(data.ex2$Depth)
data.ex2
str(data.ex2)
This outputs what I would expect:
> str(data.ex2)
'data.frame': 12 obs. of 4 variables:
$ Year : Factor w/ 3 levels "1999","2000",..: 1 1 1 1 2 2 2 2 3 3 ...
$ Depth : Factor w/ 4 levels "10","15","20",..: 1 2 3 4 1 2 3 4 1 2 ...
$ Replicate1: num 14.3 15.1 16.7 17.3 16.3 17.4 18.6 20.9 22.9 23.9 ...
$ Replicate2: num 14.7 15.6 16.9 17.9 16.4 17.2 19.6 21.3 22.7 23.3 ...
But something is not causing my anova to carry through...this is what I
have.
ANOVA = aov(Replicate1~Year*Depth,data=data.ex2)
summary(ANOVA)
which outputs:
> summary(ANOVA)
Df Sum Sq Mean Sq
Year 2 143.607 71.803
Depth 3 17.323 5.774
Year:Depth 6 2.587 0.431
There is no F-value or Pr(>F) columns.
I also can't boxplot this correctly, again following the example at that
website above they have:
boxplot(Alertness~Dosage*Gender,data=data.ex2)
which outputs:
http://old.nabble.com/file/p26258684/87o3uicpf6dt4kkdyvfv.jpeg
My code is:
boxplot(Replicate1~Year*Depth,data=data.ex2)
which outputs:
http://old.nabble.com/file/p26258684/gik02vyhvvbmcvw3ia2h.jpeg
This is incorrect, it's multiplying my factors but I thought that when I did
the str() on my data it recognized the Year and Depth as factors, not
numbers or integers.
My csv file is:
http://old.nabble.com/file/p26258684/hmwk1pt2.csv hmwk1pt2.csv
Any help on what is going one would be greatly appreciated because I need to
perform one-way, two-way, nested, and factorial anovas but I first need to
solve this problem before I can continue.
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