Your continuous variable requires one parameter (i.e., the slope). Your two-level categorical variable requires one parameter because of the 'effect coding.' Your intercept requires one parameter. So there are three degrees of freedom in the whole model that is tested by the analysis of variance but there is only one DF associated with the individual test for each estimate.

The symbol F( 1, 83 ) indicates that the F ratio (i.e., MS Model / MS Error) has 1 DF in the numerator and 83 DF in the denominator.

Have you studied linear models or linear regression? These topics are basic lessons in these subjects. Either way, these reports are explained by selecting Help > Books > Fitting Linear Models or by using search in the Help system.

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