Beta Function

The beta function forms part of the definition of several distributions:

It is convenient to define the beta function in terms of the gamma function:

The graph below shows the range of values of the Beta function for the values of a and b used in the documentation for the Beta distribution.

Excel

Excel does not have a dedicated Beta function, however, it is possible to use the gammaln function which returns the log (to base e) of the gamma function, thus values beta function can be obtained using this formula:

beta(a,b) = exp(gammaln(a)+gammaln(b)-gammaln(a+b))

Page Modified: 20-Jun-2008

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