betacdf (Statistics Toolbox)

Beta cumulative distribution function (cdf)

Syntax

```
p = betacdf(X,A,B)
```

Description

p = betacdf(X,A,B) computes the beta cdf at each of the values in X using the corresponding parameters in A and B. Vector or matrix inputs for X, A, and B must all have the same size. A scalar input is expanded to a constant matrix with the same dimensions as the other inputs. The parameters in A and B must all be positive, and the values in X must lie on the interval [0,1].

The beta cdf for a given value x and given pair of parameters a and b is

where B( · ) is the Beta function. The result, p, is the probability that a single observation from a beta distribution with parameters a and b will fall in the interval [0,x].

Examples

x = 0.1:0.2:0.9;
a = 2;
b = 2;
p = betacdf(x,a,b)
p = 
    0.0280    0.2160    0.5000    0.7840    0.9720
a = [1 2 3];
p = betacdf(0.5,a,a)
p =
    0.5000    0.5000    0.5000

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