The Excel Chiinv function calculates the inverse of the right-tailed probability of the chi-square distribution.
Syntax: CHIINV( probability, degrees_freedom )
|probability||–||The probability of the chi-square distribution, for which you want to find the value of x|
The number of degrees of freedom (must be an integer between 1 and 1010)
(If the supplied degrees_freedom is a decimal, this is truncated to an integer)
Relationship Between Chiinv and Chidist
The Chiinv function is the inverse of the Excel Chidist function. I.e., for a supplied probability, the Chiinv function uses an iterative method to find the value of x such that:
Chiinv Function Examples
The spreadsheets below show 5 different examples of the Excel Chiinv function, used to calculate the inverse right-tailed chi-square distribution. The formulas are shown in the spreadsheet on the left, and the results are shown in the spreadsheet on the right.
Chiinv Function Errors
If you get an error from the Excel Chiinv function this is likely to be one of the following :
|#NUM!||–||Occurs if either the supplied probability value is ≤ 0 or > 1 or the supplied degrees_freedom argument is <1 or >1010|
|#VALUE!||–||Occurs if either of the supplied arguments are not recognised as numeric values|