Odp: boxplot from mean and SD data
On Aug 24, 2011, at 13:18 , Petr PIKAL wrote:
Hi
Dear all, I have a dataset of 3 categorical factors, the mean and the standard deviation of each value. I want to use these values to plot a boxplot, grouped by each of the 3 categorical factors (24 boxplots in total). I don't have a clue on how to do the boxplot from mean and SD data already
calculated. I am afraid that you can not do it.
Or, you can't do it without modifying the definition of a boxplot. There are variations in which the box is mean +/- 2SD and the whiskers show the range, but I consider that a doubleplusungood idea -- box plots should be box plots!
Only if you you accept assumption that distribution within each factor is normal and therefore median equals mean. You can than also use 25 an 75 percentile for box construction. see ?boxplot and ?bxp for internals of plotting function. One possibility also is to generate values by mean and sd parameters to rnorm, although I do not see the reason for doing it. Regards Petr
Thanks in advance [[alternative HTML version deleted]]
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