Crab spiders hiding on flowers. Refer to the Behavioral Ecology (Jan. 2005) experiment on...

Crab spiders hiding on flowers. Refer to the Behavioral Ecology (Jan. 2005) experiment on crab spiders’ use of camouflage to hide from predators (e.g., birds) on flowers, presented. Researchers at the French Museum of Natural History collected a sample of 10 adult female crab spiders, each sitting on the yellow central part of a daisy, and measured the chromatic contrast between each spider and the flower. The data (for which higher values indicate a greater contrast, and, presumably, an easier detection by predators) are shown in the accompanying table and saved in the SPIDER file. The researchers discovered that a contrast of 70 or greater allows birds to see the spider. Of interest is whether or not the true mean chromatic contrast of crab spiders on daisies is less than 70

Based on Thery, M., et al. “Specific color sensitivities of prey and predator explain camouflage in different visual systems.” Behavioral Ecology , Vol. 16, No. 1, Jan. 2005 ( Table 1 ).

a. Define the parameter of interest, μ

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b. Set up the null and alternative hypotheses of interest.

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c. Find   and s for the sample data, and then use these values to compute the test statistic.

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d.Give the rejection region for α = .01.

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e. State the appropriate conclusion in the words of the problem.

Crab spiders hiding on flowers. Crab spiders use camouflage to hide on flowers while lying in wait to prey on other insects. Ecologists theorize that this natural camouflage also enables the spiders to hide from their own predators, such as birds and lizards. Researchers at the French Museum of Natural History conducted a field test of this theory and published the results in Behavioral Ecology (Jan. 2005). They collected a sample of 10 adult female crab spiders, each sitting on the yellow central part of a daisy. The chromatic contrast between each spider and the flower it was sitting on was measured numerically with a spec- troradiometer, on which higher values indicate a greater contrast (and, presumably, easier detection by predators). The data for the 10 crab spiders are shown in the following table and saved in the SPIDER file.

Based on Thery, M., et al. “Specific color sensitivities of prey and predator explain camouflage in different visual systems.” Behavioral Ecology, Vol. 16, No. 1, Jan. 2005.

Conclusions and Consequences for a Test of Hypothesis