[R] Learning ANOVA

[Stephen Liu]

----- Original Message ----
From: "Liaw, Andy" <andy_liaw at merck.com>
To: Stephen Liu <satimis at yahoo.com>; r-help at r-project.org
Sent: Sat, August 14, 2010 12:48:33 AM
Subject: RE: [R]  Learning ANOVA

>Note the names of the variables here.  They don't match what you tried
>to use in your boxplot() call below.  Where did you get the idea that
>there are "DO" and "Stream" in the "test01" data frame?


Hi Andy,


I followed following video to proceed;

ANOVA in R 
http://www.youtube.com/watch?v=Dwd3ha0P8uw&feature=related


I fixed it with;

> boxplot(test01$count ~ test01$spray)


Continued:

> InsectSprays.aov <-(test01$count ~ test01$spray)
> summary(InsectSprays.aov)
Length   Class    Mode 
      3 formula    call 

Seems having problem here.


> TukeyHSD(InsectSprays.aov)
Error in UseMethod("TukeyHSD") : 
  no applicable method for 'TukeyHSD' applied to an object of class "formula"

I was still stuck here.


B.R.
Stephen L




----- Original Message ----
From: "Liaw, Andy" <andy_liaw at merck.com>
To: Stephen Liu <satimis at yahoo.com>; r-help at r-project.org
Sent: Sat, August 14, 2010 12:48:33 AM
Subject: RE: [R]  Learning ANOVA

From: Stephen Liu
> 
> Hi folks,
> 
> R on Ubuntu 10.04 64 bit.
> 
> Performed following steps on R:-
> 
> ### to access to the object
> > data(InsectSprays)
> 
> ### create a .csv file
> > write.csv(InsectSprays, "InsectSpraysCopy.csv")
> 
> 
> On another terminal
> $ sudo updatedb
> $ locate InsectSpraysCopy.csv
> /home/userA/InsectSpraysCopy.csv
> 
> 
> ### Read in some data
> > test01 <- read.csv(file.choose(), header=TRUE)
> 
> Enter file name: /home/userA/InsectSpraysCopy.csv
> 
> 
> ### Look at the data
> > test01
>     X count spray
> 1   1    10     A
[snipped]

Note the names of the variables here.  They don't match what you tried
to use in your boxplot() call below.  Where did you get the idea that
there are "DO" and "Stream" in the "test01" data frame?

Andy


> ### Create a side-by-side boxplot of the data
> boxplot(test01$DO ~ test01$Stream)
> Error in model.frame.default(formula = test01$DO ~ test01$Stream) : 
>   invalid type (NULL) for variable 'test01$DO'
> 
> 
> I was stucked here.  Pls help.  TIA
> 
> 
> B.R.
> Stephen L
> 
> 
> 
> ----- Original Message ----
> From: Stephen Liu <satimis at yahoo.com>
> To: r-help at r-project.org
> Sent: Fri, August 13, 2010 11:34:31 AM
> Subject: [R] Learning ANOVA
> 
> Hi folks,
> 
> 
> File to be used is on;
> data(InsectSprays)
> 
> 
> I can't figure out where to insert it on following command;
> test01 <- read.csv(fil.choose(), header=TRUE)
> 
> Please help.  TIA
> 
> B.R.
> 
> 
> 
> 
> ______________________________________________
> R-help at r-project.org mailing list
> 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.
> 
> 
> 
> 
> ______________________________________________
> R-help at r-project.org mailing list
> 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.
> 
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