[Matplotlib-users] incorrect boxplot?

[<jas...@cr...>]

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