Estimated Marginal Means

This table displays the model-estimated marginal means and standard errors of Amount spent at the factor levels of Who shopping for. This table is useful for exploring the differences between the levels of this factor. In this example, a customer who shops for him- or herself is expected to spend about $308.53, while a customer with a spouse is expected to spend $370.34, and a customer with dependents will spend $459.44. To see whether this represents a real difference or is due to chance variation, look at the test results.

The individual tests table displays two simple contrasts in spending.

• The contrast estimate is the difference in spending for the listed levels of Who shopping for.
• The hypothesized value of 0.00 represents the belief that there is no difference in spending.
• The Wald F statistic, with the displayed degrees of freedom, is used to test whether the difference between a contrast estimate and hypothesized value is due to chance variation.
• Since the significance values are less than 0.05, you can conclude that there are differences in spending.

The values of the contrast estimates are different from the parameter estimates. This is because there is an interaction term containing the Who shopping for effect. As a result, the parameter estimate for shopfor=1 is a simple contrast between the levels Self and Self and Family at the level From both of the variable Use coupons. The contrast estimate in this table is averaged over the levels of Use coupons.

The overall test table reports the results of a test of all of the contrasts in the individual test table. Its significance value of less than 0.05 confirms that there is a difference in spending among the levels of Who shopping for.

This table displays the model-estimated marginal means and standard errors of Amount spent at the factor levels of Use coupons. This table is useful for exploring the differences between the levels of this factor. In this example, a customer who does not use coupons is expected to spend about $319.65, and those who do use coupons are expected to spend considerably more.

The individual tests table displays three simple contrasts, comparing the spending of customers who do not use coupons to those who do.

Since the significance values of the tests are less than 0.05, you can conclude that customers who use coupons tend to spend more than those who don't.

The overall test table reports the results of a test of all the contrasts in the individual test table. Its significance value of less than 0.05 confirms that there is a difference in spending among the levels of Use coupons. Note that the overall tests for Use coupons and Who shopping for are equivalent to the tests of model effects because the hypothesized contrast values are equal to 0.

This table displays the model-estimated marginal means, standard errors, and confidence intervals of Amount spent at the factor combinations of Who shopping for and Use coupons. This table is useful for exploring the interaction effect between these two factors that was found in the tests of model effects.

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