Inverse of the survival function¶
-
chdtri(k, y)¶ Finds the Chi-square argument x such that the integral from x to infinity of the Chi-square density is equal to the given cumulative probability y.
Parameters:
Description¶
This is accomplished using the inverse gamma integral function and the relation:
x/2 = igami(k/2, y)
Accuracy¶
See igami() for accuracy.
Error messages¶
| message | condition | value returned |
|---|---|---|
| chdtri domain | y < 0 or y > 1 | 0 |
| k < 1 |
Reference: http://www.netlib.org/cephes/doubldoc.html#chdtri