Mussel settlement patterns on algae. Mussel larvae are in great abundance in the drift material that washes up on Ninety Mile Beach in New Zealand. These larvae tend to settle on algae. Environmentalists at the University of Auckland investigated the impact of the type of algae on the abundance of mussel larvae in drift material (Malacologia, Feb. 8, 2002). Drift material from three different wash-up events on Ninety Mile Beach was collected; for each washup, the algae was separated into four strata: coarse-branching, medium-branching, fine- branching, and hydroid algae. Two samples were randomly selected for each of the 3 * 4 = 12 event–

strata combinations, and the mussel density (percent per square centimeter) was measured for each. The data were analyzed as a complete 3 * 4 factorial design. The ANOVA summary table is as follows:

a. Conduct the appropriate ANOVA F-tests (at a = .05)
and interpret the results.

b. Tukey multiple comparisons of the four algae strata means (at a = .05) are summarized in the accompanying table. Which means are significantly different?

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Source Event Strata Interaction Error Total 123622 df F p-Value .35 >.05 217.33 .05