Chiinv function

Returns the inverse of the one-tailed probability of the chi-squared distribution. If probability = CHIDIST(x,...), then CHIINV(probability,...) = x. Use this function to compare observed results with expected ones to decide whether your original hypothesis is valid.

Syntax

CHIINV(probability,degrees_freedom)

Probability     is a probability associated with the chi-squared distribution.

Degrees_freedom     is the number of degrees of freedom.

Remarks

• If either argument is nonnumeric, CHIINV returns the #VALUE! error value.

• If probability < 0 or probability > 1, CHIINV returns the #NUM! error value.

• If degrees_freedom is not an integer, it is truncated.

• If degrees_freedom < 1 or degrees_freedom ≥ 10^10, CHIINV returns the #NUM! error value.

CHIINV uses an iterative technique for calculating the function. Given a probability value, CHIINV iterates until the result is accurate to within ± 3x10^-7. If CHIINV does not converge after 100 iterations, the function returns the #N/A error value.

Example

Probability	Degrees_freedom	Formula	Description (Result)
0.05	10	=CHIINV([Probability],[Degrees_freedom])	Inverse of the one-tailed probability of the chi-squared distribution (18.30703)