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.
A mixture of two unimodal distributions with differing means is not necessarily bimodal, however. The combined distribution of heights of men and women is sometimes used as an example of a bimodal distribution, but in fact the difference in mean heights of men and women is too small relative to their standard deviations to produce bimodality. A mixture of two normal distributions with equal standard deviations is bimodal only if their means differ by at least twice the common standard deviation.
US Patent Issued to Arkema France on March 29 for "Impact Modified Acrylics Having a Bimodal Distribution of Impact Modifier Sizes" (Pennsylvania, California Inventors)
Apr 05, 2011; ALEXANDRIA, Va., April 5 -- United States Patent no. 7,915,346, issued on March 29, was assigned to Arkema France (Colombes,...