Metabolic rates in caterpillars. Professor Harihuko Itagaki and his students have been measuring metabolic rates in tobacco hornworm caterpillars (Manduca sexta) for years. The researchers do not want the metabolic rates to depend on which analyzer they use to obtain the measurements. They therefore make 6 repeated measurements on each of 3 caterpillars with each of 3 analyzers.9
(a) Use software to give the two-way ANOVA table. The researchers used caterpillar as a blocking variable because metabolic rates vary from individual to individual. These three caterpillars are not of interest in themselves. They represent the larger population of caterpillars of this species. We should therefore avoid inference about the main effect of caterpillars.
(b) Explain why the researchers will be unhappy if there is a significant interaction between analyzer and caterpillar. What does your analysis show about the interaction?
(c) Is there a significant effect for analyzer? Do you think the researchers will be happy with this result?