[object Object],[object Object],[object Object],[object Object]
where $n$ is the number of observations, $range$ is the range of x,
$IQR$ is the inter-quartile range of x, and $s$ is the standard
deviation of x.
References
Freedman, D. and Diaconis, P. (1981)
On the histogram as a density estimator.
Zeitschrift fur Wahrscheinlichkeitstheorie und verwandte Gebiete57, 453--476.
Scott, D. W. (1979)
On optimal and data based-histograms.
Biometrika66, 605--610.
Venables, W. N. and Ripley, B. D. (1999)
Modern Applied Statistics with S-PLUS, Third Edition, Springer.