Data Analysis with Microsoft Excel: Updated for Office 2007

294 Fundamentals of Statistics

Figure 7-17

χ^2

distribution

Unlike the normal distribution and t distribution, the x^2 distribution is

limited to values$ 0. However, like the t distribution, the x^2 distribution

involves a single parameter—the degrees of freedom. When the degrees of

freedom are low, the distribution is highly skewed. As the degrees of free-

dom increase, the weight of the distribution shifts farther to the right and

becomes less skewed. To see how the shape of the distribution changes, try

changing the degrees of freedom in the worksheet.

To increase the degrees of freedom for the x^2 distribution:

1 Click the Degrees of freedom spin arrow and increase the degrees of

freedom to 3.

The distribution changes shape as shown in Figure 7-18.

Figure 7-18

χ^2

distribution

with 3

degrees of

freedom

Critical boundary