Command Summary

Finds the probability of an interval of the χ² distribution, and graphs this distribution with the interval's area shaded.

Command Syntax

Press:

1. 2ND DISTR to access the distribution menu
2. RIGHT to select the DRAW submenu
3. 3 to select Shadeχ²(, or use arrows

TI-83/84/+/SE

2 bytes

Shadeχ²( is equivalent to χ²cdf( in terms of the probability it calculates: if a random variable follows the χ² distribution, you can use it to calculate the probability that the variable's value falls in a certain interval. However, in addition to calculating the probability, this command also draws the χ² curve, and shades the interval whose area represents the probability you want.

Note that this command does not actually return the value it calculates in Ans or anywhere else: it's merely displayed on the graph. If you're going to use the value in further calculations, you'll have to use χ²cdf( as well.

The Shadeχ²( command takes three arguments. lower and upper identify the interval you're interested in. df specifies the degrees of freedom (selecting from an infinite family of χ² distributions).

Thus, the following code would find the probability of χ² between 0 and 1 on a χ² distribution with 2 degrees of freedom, and shade this interval:

```:Shadeχ²(0,1,2
```