P_chi2
Probability integral for Chi-squared distribution.
 
Loading        LOADSUB ALL FROM "IGAMMA.HTS"
or LOADSUB FROM "MATHLIB.HTS"
 
Usage                INTEGER N
REAL X,Y
Y=FNP_chi2(N,X)
 
Description                
FNP_chi2 returns the value of the probability integral of the univariate chi-squared (χ²) probability density function with parameter n. This integral, P(x;n), is defined by the expression
X is often written as ²; among other uses, this notation emphasizes the fact that this integral is only nonzero for values of x 0. Although P is sometimes defined for n < 0, most implementations, including this one, restrict P to being defined for n 0.
 
                                         P(x;n)
                                 
Errors
FNP_chi2 causes an HTBasic error if its arguments are not of the types listed in the USAGE section, above, or if n is negative.
 
See Also
F_chi2, Q_chi2