Survival function

chdtrc(k, x)

Returns the area under the right hand tail (from x to infinity) of the Chi square probability density function with k degrees of freedom.

Parameters:
  • k (int) – degrees of freedom
  • x (float) – positive Chi square variable

Description

The incomplete gamma integral is used according to the formula:

chdtr(k, x) = igamc(k/2, x/2)

The arguments must both be positive.

Accuracy

See igamc() for accuracy.

Error messages

message condition value returned
chdtrc domain x < 0 or v < 1 0

Reference: http://www.netlib.org/cephes/doubldoc.html#chdtrc