Dear all, 
I want to use the histogtam as a density estimator, with the binwidths calculated using scott's formula which is
binwidth = 3.49*ST.dev.*n^(-1/3)
for the following data  (30 data points)
12-9-3-6-1-23-21-7-18-16-15-4-19-22-20-2-3-18-8-10-1-7-5-4-11-12-3-9-19-7
so first,I' ve tried this manually, and substituted in the above formula and I got
st.dev.=7.02745
and thus the binwidth=7.89313

But when I used hist with breaks = "scott", that is
h<-hist(x,breaks="scott")
I got the breaks in the histogram object = 0  10   20   30
that is, the binwidth used is equal to 10 not 7.89313??
I don't know why? 
shouldn't they be exactly the same??
Thanks a lot,
Maram.


      
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