Contrasts

The Contrasts report lists model effects, a contrast value, Lenth t-ratios, individual and simultaneous p-values, and aliases (if there are any). Effects are entered into the analysis following a hierarchical ordering. See Order of Effect Entry. Effects that have an Individual p-Value less than 0.10 are selected.

Term

Name of the factor.

Contrast

Estimate for the factor. For orthogonal designs, this number is the same as the regression parameter estimate. This is not the case for non-orthogonal designs. An asterisk might appear next to the contrast, indicating a lack of orthogonality.

Bar Chart

Shows the Lenth t-ratios with blue vertical lines that indicate a value that is significant at the 0.10 level.

Lenth t-Ratio

Lenth’s t-ratio, calculated as Contrast/PSE, where PSE is Lenth’s Pseudo-Standard Error. See Lenth’s Pseudo-Standard Error.

Individual p-Value

Analogous to the standard p-values for a linear model. Small individual p-values indicate a significant effect. Refer to Lenth’s Pseudo-Standard Error.

Note: Do not expect the p-values to be exactly the same if the analysis is re-run. The Monte Carlo method should give similar, but not identical, values if the same analysis is repeated.

Simultaneous p-Value

A multiple-comparison adjusted p-value.

Aliases

Appears only if there are exact aliases of later effects to earlier effects.