Editing Multimodal distribution (section)

==== Sturrock's index ====

A different bimodality index has been proposed by Sturrock.<ref name=Sturrock2008>{{cite journal | last1 = Sturrock | first1 = P | year = 2008 | title = Analysis of bimodality in histograms formed from GALLEX and GNO solar neutrino data | journal = Solar Physics | volume = 249 | issue = 1| pages = 1–10 | doi=10.1007/s11207-008-9170-3|arxiv = 0711.0216 |bibcode = 2008SoPh..249....1S | s2cid = 118389173 }}</ref>

This index (''B'') is defined as

<math display="block"> B = \frac{ 1 }{ N } \left[ \left( \sum_1^N \cos ( 2 \pi m \gamma ) \right)^2 +  \left( \sum_1^N \sin ( 2 \pi m \gamma ) \right)^2 \right] </math>

When ''m'' = 2 and ''γ'' is uniformly distributed, ''B'' is exponentially distributed.<ref name=Scargle1082>{{cite journal | last1 = Scargle | first1 = JD | year = 1982 | title = Studies in astronomical time series analysis. II – Statistical aspects of spectral analysis of unevenly spaced data | journal = The Astrophysical Journal | volume = 263 | issue = 1| pages = 835–853 | doi=10.1086/160554 | bibcode=1982ApJ...263..835S}}</ref>

This statistic is a form of [[periodogram]]. It suffers from the usual problems of estimation and spectral leakage common to this form of statistic.