On 2009-09-14 13:49 PM, Gökhan Sever wrote: > > > On Mon, Sep 14, 2009 at 12:30 PM, <jason-s...@creativetrax.com > <mailto:jason-s...@creativetrax.com>> wrote: > > I tried the following (most output text is deleted): > > In [1]: ob1=[1,1,2,2,1,2,4,3,2,2,2,3,4,5,6,7,8,9,7,6,4,5,5] > In [2]: import matplotlib.pyplot as > plt > In [3]: > plt.figure() > In [4]: > plt.boxplot(ob1) > In [5]: > plt.savefig('test.png') > In [6]: import > scipy.stats > In [7]: > scipy.stats.scoreatpercentile(ob1,75) > Out[7]: 5.5 > > > Note that the 75th percentile is 5.5. R agrees with this calculation. > However, in the boxplot, the top of the box is around 6, not 5.5. Isn't > the top of the box supposed to be at the 75th percentile? > > Thanks, > > Jason > > -- > Jason Grout > > > From matplotlib/lib/matplotlib/axes.py > > You can see how matplotlib calculating percentiles. And yes it doesn't > conform with scipy's scoreatpercentile() > > > # get median and quartiles > q1, med, q3 = mlab.prctile(d,[25,50,75]) > > I[36]: q1 > O[36]: 2.0 > > I[37]: med > O[37]: 4.0 > > I[38]: q3 > O[38]: 6.0 > > > Could this be due to a rounding? I don't know, but I am curious to hear > the explanations for this discrepancy.
prctile does not handle the case where the exact percentile lies between two items. scoreatpercentile does. -- Robert Kern "I have come to believe that the whole world is an enigma, a harmless enigma that is made terrible by our own mad attempt to interpret it as though it had an underlying truth." -- Umberto Eco ------------------------------------------------------------------------------ Let Crystal Reports handle the reporting - Free Crystal Reports 2008 30-Day trial. Simplify your report design, integration and deployment - and focus on what you do best, core application coding. Discover what's new with Crystal Reports now. http://p.sf.net/sfu/bobj-july _______________________________________________ Matplotlib-users mailing list Matplotlib-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/matplotlib-users
