Bimodal distribution

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"Bimodal" redirects here. For the musical concept, see Bimodality.

Figure 1. A simple bimodal distribution, in this case a mixture of two normal distributions with the same variance but different means. The figure shows the probability density function (p.d.f.), which is an average of the bell-shaped p.d.f.s of the two normal distributions.

Figure 2. Histogram of body lengths of 300 weaver ant workers^[1].

Figure 3. A bivariate, multimodal distribution.

In statistics, a bimodal distribution is a continuous probability distribution with two different modes. These appear as distinct peaks (local maxima) in the probability density function, as shown in Figure 1.

Examples of variables with bimodal distributions include the time between eruptions of certain geysers, the color of galaxies, the size of worker weaver ants, the age of incidence of Hodgkin's lymphoma, the speed of inactivation of the drug isoniazid in US adults, and the absolute magnitude of novae.

Contents

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• 1 Mixture distributions
• 2 Summary statistics
• 3 Multimodality