Help: Beanplots calculating wrong average
Hi Michael, Looking at the help for beanplot(), note that the 'log' option defaults to 'auto' which means the function will automatically log-transform data like yours. This also implies that the mean it shows is the geometric mean, not the arithmetic mean. As you note, the transformation doesn't affect the median. If you don't want this behavior, I think setting log="" will do the trick. Hope this helps. Tom Wainwright
On 11/24/2009 03:52 AM, Michael Hopgood wrote:
Hi there, I have a set of data that looks like this: As1988<-c(1254.0, 22.0, 4.2, 1081.0, 35.0, 6.0, 1772.0, 192.0, 7.6) The mean of this (as calculated by R) is: 485.9778 The median of this (as calculated by R) is: 35 If I then make a beanplot(As1988), I find that the beanline (average) is now 77.68561 while the beanline (median) is 35.39739 (using the locator function to check the graph and log axis). While I can understand the small discrepancy of the median(mouse hovering over the line), I am at a loss to explain the huge difference between the means. Is this a flaw in the package or is there something I am missing? My gut feeling is that the log scales are affecting the calculations somehow. Sincerely, Michael Hopgood [[alternative HTML version deleted]]
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Tom Wainwright NOAA Northwest Fisheries Science Center Newport, Oregon ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ The contents of this message are mine personally and do not necessarily reflect any position of the Government or the National Oceanic and Atmospheric Administration. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~