Manuals/calci/GAMMAINV

GAMMAINV (probability,alpha,beta,accuracy,somenumberofiterations)

• $probability$ is the probability value associated with gamma distribution
• $alpha(\alpha )$ & $beta(\beta )$ are the values of the shape and rate parameters.
• $accuracy$ gives accurate value of the solution.
• $somenumberofiterations$ is any positive integer.
  • GAMMAINV(),returns the inverse of the gamma cumulative distribution.

Description

• This function gives the inverse value of Cumulative Gamma Probability Distribution.
• This distribution is the Continuous Probability Distribution on the positive real line and it is of the reciprocal of a variable distributed according to the gamma distribution with two parameters $\alpha$ & $\beta$.
• It is used in Bayesian statistics.
• In $GAMMAINV(probability,alpha,beta,accuracy,somenumberofiterations)$ , $probability$ is the probability value associated with Gamma Distribution,$alpha$ is called shape parameter and $beta$ is the rate parameter of the distribution.
• If $GAMMADIST(x,alpha,beta,cumulative,accuracy)=prob$, then $GAMMAINV(probability,alpha,beta,accuracy,somenumberofiterations)=x$.
• GAMMAINV use 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 non-numeric
2.$alpha\leq 0$ or $beta\leq 0$
3.$probability<0$ or $probability>1$

Examples

1. =GAMMAINV(0.65189,2,5) = 11.1335534510
2. =GAMMAINV(0.006867292,5,7) = 8.155481331
3. =GAMMAINV(0.1543869,9,3) = 18.0467153645
4. =GAMMAINV(1,9,3) = 82.51739521528073
5. =GAMMAINV(1.1,9,3) = NAN, because $prob>1$

Related Videos

GAMMA Distribution

See Also

• GAMMADIST
• GAMMALN

References

Gamma Distribution

• List of Main Z Functions

• Z3 home