Manuals/calci/CHIINV

CHIINV(probability,degreesoffreedom)

Description

This function gives the inverse value of One_tailed probability of the Chi-squared Distribution.
It is called Inverted-Chi-square Distribution and it is a Continuous Probability Distribution of a positive-valued random variable.

Degrees of freedom $df$ = $(r-1)(c-1)$ .
The $\chi ^{2}$ static used to compare the observed value in each table to the value which would be the expected under the assumption.
If $X$ has the chi-squared distribution with n degrees of freedom, then according to the definition, ${\frac {1}{X}}$ has the Inverse-chi-squared distribution with $n$ degrees of freedom;
If $CHIDIST(x,df)=prob$ , then $CHIINV(prob,df)=x$ .
CHIINV 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. $df$  value is not an integer
3. $df<1$ or  $df>10^{10}$ 
4.Also  $prob<0$  or  $prob>1$ .

The syntax is to calculate CHIINV in ZOS is .
- Where $probability$ is the value associated with the Chi-squared Distribution
- $degreesoffreedom$ is the number of Degrees of Freedom
For e.g.,CHIINV(0.0257,3)