Manuals/calci/BETAINV

BETAINV(prob,alpha,beta,a,b)

• Where prob is the probability value associated with the beta distribution.
• Alpha& beta are the values of the shape parameter.
• a&b the lower and upper limit to the interval of x.

Description

• This function gives the inverse value of cumulative beta probability distribution.
• It is called inverted beta function or beta prime.
• In $BETAINV(prob,alpha,beta,a,b)$, prob is the probability value of the associated with beta distribution, alpha and beta are the values of the two positive shape parameters and a and b are the lower and upper limit. *Normally the limit values are optional, i.e., when we are giving the values of a&b then the result value is from a and b, otherwise when we are omitting the values a and b by default it will consider a=0 and b=1, so the result value is from 0 and1.
• If BETADIST(x,alpha,beta,a,b)=prob, then BETAINV(prob,alpha,beta,a,b)=x.
• BETAINV using the iterating method to find the value of x.suppose the iteration has not converged after 100 searches, then the function gives the error result.
• This function will give the error result when

1. Any one of the arguments are nonnumeric
2. alpha or beta<=0
3. x<a ,x>b, or a=b
4. we are not mentioning the limit values a and b, by default it will consider the standard cumulative beta distribution, a= 0 and b= 1.

Examples

1. BETAINV(0.2060381025,5,9,2,6)=3
2. BETAINV(0.359492343,8,10)=0.399999976(EXCEL) is approximate to 0.4=1.75(calci)
3. BETAINV(0.685470581,5,8,2,6)= 3.78378773(excel)=3.75(calci)
4. BETAINV(0.75267,1,7,7,9)=7.361844063(Excel)=7.25(calci)
5. BETAINV(0.5689,-2,4,3,5)=NAN, because alpha<0.

See Also

• BETADIST
• All Functions

References

Beta Distribution