# CHIDIST

Returns the one-tailed probability of the chi-squared distribution. The χ2 distribution is associated with a χ2 test. Use the χ2 test to compare observed and expected values. For example, a genetic experiment might hypothesize that the next generation of plants will exhibit a certain set of colors. By comparing the observed results with the expected ones, you can decide whether your original hypothesis is valid.

Syntax

CHIDIST(x,degrees_freedom)

X     is the value at which you want to evaluate the distribution.

Degrees_freedom     is the number of degrees of freedom.

Remarks

• If either argument is nonnumeric, CHIDIST returns the #VALUE! error value.
• If x is negative, CHIDIST returns the #NUM! error value.
• If degrees_freedom is not an integer, it is truncated.
• If degrees_freedom < 1 or degrees_freedom > 10^10, CHIDIST returns the #NUM! error value.
• CHIDIST is calculated as CHIDIST = P(X>x), where X is a χ2 random variable.

Example

The example may be easier to understand if you copy it to a blank worksheet.

• Create a blank workbook or worksheet.
• Select the example in the Help topic.

Note   Do not select the row or column headers.

Selecting an example from Help
• Press CTRL+C.
• In the worksheet, select cell A1, and press CTRL+V.
• To switch between viewing the results and viewing the formulas that return the results, press CTRL+` (grave accent), or on the Formulas tab, in the Formula Auditing group, click the Show Formulas button.
A B
Data Description
18.307 Value at which you want to evaluate the distribution
10 Degrees of freedom
Formula Description (Result)
=CHIDIST(A2,A3) One-tailed probability of the chi-squared distribution, for the above terms (0.050001)

Applies to:
Excel 2003