Fixed Effects Parameter Estimates
The Fixed Effects Parameter Estimates report in the Mixed Model personality provides details for the fixed effect parameters specified in the model. For each parameter, the report provides the following details:
• the estimate
• the standard error (Std Error)
• a t test for the hypothesis that the estimate equals zero
• a 95% confidence interval on the estimate
The Fixed Effects Parameter Estimates report contains the following columns:
Term
Gives the model term corresponding to the estimated parameter. The first term is always the intercept, unless you selected the No Intercept option in the Fit Model launch window. Continuous columns that are part of higher order terms are centered by default. Nominal or ordinal effects appear with values of levels in brackets. See The Factor Models for information about the coding of nominal and ordinal terms.
Note: If a continuous column is involved in a random effect, that column is not centered, even if the Center Polynomials option in the Model Specifications red triangle menu was selected.
Estimate
Gives the parameter estimate for each term. This is the estimate of the term’s coefficient in the model.
Std Error
Gives an estimate of the standard error for the parameter estimate.
DFDen
Gives the denominator degrees of freedom, that is, the degrees of freedom for error, for the effect test. DFDen is calculated using the Kenward-Roger first order approximation. See Statistical Details for the Kackar-Harville Correction.
t Ratio
Tests whether the true value of the parameter is zero. The t Ratio is the ratio of the estimate to its standard error. Given the usual assumptions about the model, the t Ratio has a Student’s t distribution under the null hypothesis.
Prob>|t|
Lists the p-value for a two-sided test of the t Ratio.
95% Lower
Shows the lower 95% confidence limit for the parameter. You can change the α level in the Fit Model window by selecting Set Alpha Level from the Model Specification red triangle menu.
95% Upper
Shows the upper 95% confidence limit for the parameter. You can change the α level in the Fit Model window by selecting Set Alpha Level from the Model Specification red triangle menu.