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The χ²pdf( Command

Command Summary Command Syntax Calculator Compatibility Token Size
Evaluates the χ² probability density function at a point. χ²pdf(x, df TI-83/84/+/SE 2 bytes

Press:
1. 2ND DISTR to access the distribution menu
2. 6 to select χ²pdf(, or use arrows.
Press 7 instead of 6 on a TI-84+/SE with OS 2.30 or higher.

The χ²pdf( Command

χ²pdf( is the χ² probability density function.

Since the χ² distribution is continuous, the value of χ²pdf( doesn't represent an actual probability — in fact, one of the only uses for this command is to draw a graph of the χ² curve. You could also use it for various calculus purposes, such as finding inflection points.

The command takes two arguments: the value at which to evaluate the p.d.f., and df, the number of 'degrees of freedom'.

Formulas

The value of χ²pdf( is given by

\[\operatorname{\chi^2pdf}(x,k)=\frac{(1/2)^{k/2}}{(k/2-1)!}\,x^{k/2-1}e^{-x/2}\]
Authors: KG