[R] Make barplot with error bars, anova out of a table

[Paul Johnson]

Hi

On Thu, Apr 11, 2013 at 6:43 AM, Simza <alex_steckbauer at gmx.at> wrote:
> Helo everybody,
> I'm new to R and have some issues with my data in R.
>
> My raw data look like that:
>
> ID Day size 1 1 7 1 1 7.2 1 1 7.1 2 1 7.3 2 1 7.4 2 1 7.2 3 1 7 3 1 7.1 3 1
> 7.5 4 1 7.3 4 1 7.2 4 1 7.6 1 2 7 1 2 7.2 1 2 7.1 2 2 7.1 2 2 7.4 2 2 7.2 3
> 2 7.5 3 2 7.1 3 2 7.5 4 2 7.2 4 2 7.2 4 2 7.3 1 3 7.4 1 3 7.2 1 3 7.1 2 3
> 7.2 2 3 7.4 2 3 7.2 3 3 7.4 3 3 7.2 3 3 7.5 4 3 7.4 4 3 7.2 4 3 7.7
>
> What I want to do is:
> 1) calculate the significant difference of the size for the 4 groups but
> each day separately!)? E.g. difference in size between ID 1:2, 1:3, 1:4,
> 2:3, 2:4, 3:4 for each day.
>
> I already tried lm() and anova() but just get the difference between day, ID
> and size. I also tried to separate the data per hand but I think there
> should be a way in "R" to do that automatically!? Moreover, I was searching
> the web for similar examples but couln't find anything useful so far.
>
> 2) to make a barplot with error bars of the standart error (from the mean).
> So far I used:
> barplot(matrix(c(Rtest.dat$pH.mean),nr=3), beside=T,
> col=c("black","grey","white"), main="pH", names.arg=c("Green", "Yellow",
> "Blue", "Red"), ylab="pH") legend("topright", c("Day 1","Day 2","Day 3"),
> cex=0.6, bty="n", fill=c("black","grey","white"))
> But I have problems to add the error bars. Also here I already searched the
> web but couldn't manage to get a code working for my data.
>
R has a function called "arrows" that we use to draw intervals like
that. You have to calculate the intervals, of course, that's up to
you, and then draw them on the plot.

As luck would have it, I've been working a vaguely similar type of plot,

http://pj.freefaculty.org/scraps/plot-factor-proto.pdf

and I'm going to upload the R code that produces that plot. It shows
how to do arrows and such. I'm calling this a WorkingExample

http://pj.freefaculty.org/R/WorkingExamples/plot-regression-factors-1.R

> 3) and the last thing I would need is to add * or letters (a,b,...) to the
> graph, indicating the significant difference between them.
>
Try text() to insert stuff on plots. * is writable by text.


> Hope someone can help me!
>
> Thanks for your help!!
>
>
>
> --
> View this message in context: http://r.789695.n4.nabble.com/Make-barplot-with-error-bars-anova-out-of-a-table-tp4663979.html
> Sent from the R help mailing list archive at Nabble.com.
>
> ______________________________________________
> 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.



--
Paul E. Johnson
Professor, Political Science      Assoc. Director
1541 Lilac Lane, Room 504      Center for Research Methods
University of Kansas                 University of Kansas
http://pj.freefaculty.org               http://quant.ku.edu