STEP-BY-STEP TECHNOLOGY GUIDE: Finding χ2 p-value

We will use the information from Example 32 (page 559). The steps for finding the χ2 critical values are given in the Step-by-Step Technology Guide at the end of Section 8.4 (pages 479-480).

TI-83/84

  • Step 1 Press 2nd > DISTR, then χ2 cdf(, and press ENTER.
  • Step 2 On the home screen, enter the value of χ2data, comma, 1E99, comma, degrees of freedom, close parenthesis, as shown in Figure 48. (Remember that this “E” is inserted by pressing 2nd, followed by the comma key.)
  • Step 3 Press ENTER. The results are shown in Figure 48 of Example 32.

EXCEL

  • Step 1 Select cell A1. Click the Insert Function icon fx.
  • Step 2 For Search for a Function, type chidist, click Go, then click OK.
  • Step 3 For X, enter the value of χ2data, and for Deg_freedom, enter the degrees of freedom. Excel displays the p-value in the cell in the dialog box.

562

MINITAB

  • Step 1 Click on Calc > Probability Distributions > Chi-Square.
  • Step 2 Select Cumulative probability, and enter the Degrees of freedom.
  • Step 3 For Input constant, enter the value of χ2data and click OK.
  • Step 4 Minitab displays the area to the left of χ2data in the session window. To find the p-value, subtract this area from 1.

SPSS

  • Step 1 Enter a number into the first element of the spreadsheet.
  • Step 2 Select Transform > Compute Variable…. Enter the variable name under Target Variable. Select CDF and Noncentral CDF under Function group, and double-click Cdf. Chisq under Functions and Special Variables.
  • Step 3 Replace the two question marks in Numeric Expression with the value of χ2data and the degrees of freedom, respectively. Click OK, then OK. Minimize the output window.
  • Step 4 SPSS displays the area to the left of χ2data in the data spreadsheet. To find the p-value, subtract this area from 1.

JMP

  • Step 1 Click File > New > Data Table. Enter a number into the first element of Column 1. Select Column 1 and click Cols > Formula….
  • Step 2 Select Probability from the Functions (grouped) drop-down menu, then select ChiSquare Distribution from the list below the menu.
  • Step 3 In the formula, replace x with the value of χ2data and DF with the degrees of freedom. Click OK.
  • Step 4 JMP displays the area to the left of χ2data in the data spreadsheet. To find the p-value, subtract this area from 1.

CRUNCHIT!

  • Step 1 Click Distribution Calculator and select Chi-square.
  • Step 2 For df enter the degrees of freedom.
  • Step 3 Select the Probability tab. From the drop-down menu, select >. In the box, enter the value of χ2data and click Calculate.