Crab-spiders hiding on flowers. Behavioral Ecology (January 2005) published the results of an experiment on crab-spiders' use of camouflage to hide from predators (e.g., birds) on flowers. Researchers at the French Museum of Natural History collected a sample of 10 adult female crabspiders, each sitting on the yellow central part of a daisy, and measured the chromatic contrast of each spider to the flower.
The data (where higher values indicate a greater contrast, and, presumably, an easier detection by predators) are shown in the next table. The researchers discovered that a contrast of 70 or greater allows birds to see the spider. Of interest is whether or not true mean chromatic contrast of crab-spiders on daisies is less than 70.
(a) Define the parameter of interest, μ.
(b) Setup the null and alternative hypothesis of interest.
(c) Find y‾ and s for the sample data, then use these values to compute the test statistic.
(d) Give the rejection region for α = .10.
(e) Find the p-value for the test.
(f) State the appropriate conclusion in the words of the problem.
