# The BETA.DIST function

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Welcome back to our usual blog of Excel functions from A to Z. Today we look at the BETA.DIST function.

The BETA.DIST function

In probability theory and statistics, the beta distribution is a family of continuous probability distributions defined on the interval [0, 1] parameterized by two positively shaped parameters, denoted by a (alfa) Y b (beta), that appear as exponents of the random variable and control the shape of the distribution. It has nothing to do with the beta function (integral by Euler) used in other areas of mathematics or with the beta cited as a scalar in the Capital Asset Pricing Model.

The beta distribution has been applied to model the behavior of random variables limited to intervals of finite length in a wide variety of disciplines.. As an example, has been used as a statistical description of allele frequencies in population genetics, time allocation in management systems / project control, insolation data, variability of soil properties, Proportions of minerals in rocks in stratigraphy and heterogeneity in the probability of HIV infection. transmission. Who would have thought that statistics and Excel could be so interesting?

In Bayesian inference, the beta distribution is the conjugate prior probability distribution for Bernoulli distributions, binomial, negative and geometric binomial. As an example, the beta distribution can be used in Bayesian analysis to describe initial knowledge about the probability of success, as the probability that a spacecraft successfully completes a specific mission. The beta distribution is a suitable model for the random behavior of percentages and proportions.