Documentation/How Tos/Calc: CHISQDIST function

CHISQDIST

Calculates values for a χ²-distribution.

Syntax

CHISQDIST(x; k; Cumulative)

x is the number, at which you will evaluate the χ²-distribution.

k sets the degrees of freedom for the χ²-distribution

Constraint: k must be a positive integer

Cumulative is a logical value.

In the case Cumulative=TRUE() the cumulative distribution function is used, in the case Cumulative=FALSE() the probability density function. This parameter is optional. It is set to TRUE() if missing.

Semantic

CHISQDIST(x;k;FALSE()) returns values of the probability density function for the χ²-distribution:

CHISQDIST(x;k;TRUE()) returns the left tail probability for the χ²-distribution:

Example

CHISQDIST(2.3;15;FALSE()) returns approximately 0,000209862 CHISQDIST(2.3;2;FALSE()) returns approximately 0,158318385

CHISQDIST(1.5;2;TRUE()) returns approximately 0,5276334 other valid call: CHISQDIST(1.5;2)

CHISQDIST(18;15;TRUE()) returns approximately 0,73733444

Remarks

If you need CHISQDIST(x;k;TRUE()) with a non integer parameter k, then use GAMMADIST(x;k/2;2) instead.

For to get the right tail for large values x, do not calculate 1 − CHISQDIST. It is less accurate in those cases than using CHIDIST. CHISQDIST(x;k;TRUE()) + CHIDIST(x;k) = 1.

In the density case the internal calculation uses logarithmic- and exponential function, if x >1425 or x · k > 1391000. The results are less accurate in those cases.

Issues

This function is not available in version 3.0 and earlier.

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See Also

• CHISQINV
• LEGACY.CHIDIST
• LEGACY.CHIINV
• CHITEST

• Statistical functions

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