--  Given the degrees of freedom, CHISQ.DIST returns the value
--  of the probability density function using the chi-square
--  distribution, or the cumulative distribution depending on the
--  third argument.
--
--      CHISQ.DIST ( [Value], DegFreedom, Cumulative )
--
--  The .INV functions provide the inverse calculation
--  The .RT functions return the right tail of the chi-square, they
--  do not need the Cumulative argument, which is always TRUE
--  CHISQ.DIST.RT = (1 - CHISQ.DIST)
--
--  https://en.wikipedia.org/wiki/Chi-square_distribution
DEFINE
    VAR Vals            = GENERATESERIES ( 0, 10, 0.28 )
    VAR DegFreedom      = 5
    VAR CumulativeTrue  = TRUE   -- Cumulative distribution function
    VAR CumulativeFalse = FALSE  -- Probability density function
EVALUATE
ADDCOLUMNS ( 
    Vals, 
    "ChiSquare Dist",            -- Probability density function
        FORMAT ( 
            CHISQ.DIST ( [Value], DegFreedom, CumulativeFalse ),
            "#,0.0####"
        ),
    "ChiSquare Dist Cumulative", -- Cumulative distribution function
        FORMAT ( 
            CHISQ.DIST ( [Value], DegFreedom, CumulativeTrue ),
            "#,0.0####"
        ),
    "ChiSquare Inv Cumulative",
        CHISQ.INV (  
            CHISQ.DIST ( [Value], DegFreedom, CumulativeTrue ),
            DegFreedom
        ),
    "ChiSquare Dist RT", 
        FORMAT ( 
            CHISQ.DIST.RT ( [Value], DegFreedom ),
            "#,0.0####"
        ),
    "ChiSquare RT Inv",
        CHISQ.INV.RT (  
            CHISQ.DIST.RT ( [Value], DegFreedom ),
            DegFreedom
        )
    )