# Testing hypotheses about multiple coefficients in a model

After a model has been estimated, you may wish to test hypotheses about the values of coefficients with reference to each other. For example, you may wish to test whether two or more coefficients are equal to each other, or whether they sum to one.

Wizard supports four kinds of hypothesis tests for groups of model coefficients. Each is associated with a null hypothesis, as described in the table below.

Hypothesis test | Null hypothesis | Formula
--- | --- | ---
Joint significance | Coefficients are zero | βi=0
Coefficient equality | Coefficients are equal | βi=βj
Sum-to-zero test | Coefficients sum to 0 | ∑βi=0
Sum-to-one test | Coefficients sum to 1 | ∑βi=1

To test one of these hypotheses about two or more model coefficients:

1. In the Model view, select two or more coefficients in the explanatory variables table (Command-click or Shift-click to select multiple rows)
2. Below the coefficient picture view, use the button labeled Null hypothesis to select the null hypothesis of the test you wish to perform
3. The result of the hypothesis test will appear in the coefficient picture view

Wizard performs all hypothesis tests using the Wald test. An F statistic is constructed for linear models, and a chi-squared statistic is constructed for non-linear models.

See also:

- Testing hypotheses about a single coefficient in a model
- Testing the joint significance of multiple coefficients in a model
- Viewing the p-values of a model’s explanatory variables
- About models

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