Estimated Marginal Means: Vehicle Age

Figure 1. Estimated marginal means for Vehicle age

This table displays the model-estimated marginal means, standard errors, and confidence intervals for Average cost of claims at the factor levels of Vehicle age. This table is useful for exploring the differences between the levels of this factor. In this example, the linear predictor ranges from a low of 129.85 for vehicles 10+ years old to a high of 281.89 for vehicles 0-3 years old. To see whether the values in this table represent real differences or are likely due to chance variation, look at the test results.

Table 1. Individual test results for Vehicle age
Vehicle age Repeated Contrast	Contrast Estimate	Std. Error	Wald Chi-Square	df	Sequential Sidak Sig.
Level 10+ vs. Level 8-9	-62.50	10.889	32.947	1	.000
Level 8-9 vs. Level 4-7	-63.15	9.544	43.783	1	.000
Level 4-7 vs. Level 0-3	-26.38	7.268	13.175	1	.000

The individual test results table displays the differences between successive vehicle age groups and tests whether each difference is due to chance variation. All contrasts are statistically significant, which is strong evidence that the size of claims decreases with increasing age.

Table 2. Overall test results for Vehicle age
Wald Chi-Square	df	Sig.
282.315	3	.000

The overall test table reports the results of a test of all of the contrasts in the pairwise comparisons table. This test is not equivalent to the model effects test for Vehicle age because the model effects test is performed on the transformed scale, while these estimated marginal means have been computed on the original scale