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Newbie Question About Histograms

4 messages · pfc_ivan, Peter Alspach, Eik Vettorazzi

Original
pfc_ivan
# 
Hello everyone. Just have a question , cant figure out how to make this
histogram. 

I have this table, that i stored in a variable name new.data2. Table looks
like this

Year GeoArea SmpNo Month Gear Maturity Length Age YearC
1989       1   362    10   22        1    225   1  1988
1991       1   267    10   10        1    191   1  1990
1991       1   267    10   10        1    202   1  1990
1992       1   305    10    8        1    162   1  1991
1992       1   305    10    8        1    165   1  1991
1992       1   305    10    8        1    166   1  1991
1992       1   305    10    8        1    167   1  1991
1992       1   305    10    8        1    167   1  1991
1992       1   305    10    8        1    169   1  1991
1992       1   305    10    8        1    170   1  1991

Now I need to make a histogram of Length vs YearC. I would guess that Length
would be on the Y-axis and YearC variable would be on X-axis. I have tried
many different combinations with command 'hist' but im always getting error
" 'x' must be numeric " ... I think im getting that error because of the
header which is not numeric. Any help would be appreciated. Thanks guys. 

Ivan.
pfc_ivan
# 
Also I forgot to say that The Y-axis values for each YearC would be the mean
value of all the Lenghts that happen in that YearC. Basically I cant figure
out how to put the mean values of Lengths for each YearC on Y axis. 

Thanks in advance!
Peter Alspach
# 
Kia ora Ivan

I think you might want a barplot.

?hist

under 'See Also:' states:

     Typical plots with vertical bars are _not_ histograms.  Consider
     'barplot' or 'plot(*, type = "h")' for such bar plots.
 
[The online help in R is good.]

HTH ....

Peter Alspach
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Eik Vettorazzi
# 
How about

 > dta<-read.table("clipboard",header=T)
 > means<-aggregate(dta$Length,by=list(YearC=dta$YearC),FUN=mean)
 > barplot(means[,2],names.arg=means[,1])

you may have a look at ?barplot to see (lots of) options for fine tuning 
the plot.

hth.

pfc_ivan schrieb: