Difference between revisions of "Manuals/calci/GAMMAINV"

Latest revision as of 17:12, 7 August 2018

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.
is any positive integer.
- GAMMAINV(),returns the inverse of the gamma cumulative distribution.

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  $probability>1$

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

@@ Line 2: / Line 2: @@
 *<math>probability</math> is the probability value associated with gamma distribution
 *<math>alpha(\alpha)</math> & <math>beta(\beta)</math> are the values of  the shape and rate parameters.
-*<math> accuracy </math> and <math> somenumberofiterations </math> are any positive integers.
+*<math> accuracy </math> gives accurate value of the solution.
+*<math> somenumberofiterations </math> is any positive integer.
+**GAMMAINV(),returns the inverse of the gamma cumulative distribution.
 ==Description==
@@ Line 15: / Line 17: @@
 .Any one of the arguments are non-numeric
 .<math>alpha \le 0 </math> or <math>beta \le 0 </math>
-.<math>prob < 0</math> or <math> prob > 1 </math>
+.<math>probability < 0</math> or <math> probability > 1 </math>
 ==Examples==