CHISQUARED is the jCommon module of jLab.

 CHISQUARED  The chi-squared distribution.
 
    FX=CHISQUARED(X,K) returns the chi-squared probability distribution
    with K degrees of freedom at values X, which may be an array.
 
    Usage: fx=chisquared(x,k);
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    This is part of JLAB --- type 'help jlab' for more information
    (C) 2020 J.M. Lilly --- type 'help jlab_license' for details