Cumulative distribution function¶
-
chdtr(k, x)¶ Returns the area under the left hand tail (from 0 to x) of the Chi square probability density function with k degrees of freedom.
Parameters:
Description¶
\[P(x~|~k) = \frac{1}{\Gamma (k/2)} \int_{0}^{x/2} t^{k/2-1} e^{-t} dt\]
The incomplete gamma integral is used according to the formula:
chdtr(k, x) = igam(k/2, x/2)
The arguments must both be positive.
Accuracy¶
See igam() for accuracy.
Error messages¶
| message | condition | value returned |
|---|---|---|
| chdtr domain | x < 0 or v < 1 | 0 |