# Manuals/calci/CHIINV

CHIINV (probability,degrees_freedom,Accuracy,DivisionDepthArray)

• Where is the value associated with the Chi-squared Distribution
• is the number of Degrees of Freedom.
• is the correct decimal places of the result.
• CHIINV(), returns the inverse of the one-tailed probability of the chi-squared distribution.

## 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 =.
• The static used to compare the observed value in each table to the value which would be the expected under the assumption.
• If has the chi-squared distribution with n degrees of freedom, then according to the definition, has the Inverse-chi-squared distribution with degrees of freedom;
• If , then .
• CHIINV use the iterating method to find the value of .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.degrees freedom value is not an integer
3.degrees freedom < 1  or degrees freedom>
4.Also  probability < 0  or probability>1.


## ZOS

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

## Examples

1. CHIINV(0.0001234098,2) = 18
2. CHIINV(0.2547876,5) = 6.5669999999999655
3. CHIINV(0.157299207050,1) = 1.9991000000000005
4. CHIINV(0.6785412,-1) = #N/A (DEGREESOFFREEDOM < 1)

Chi-Square Test