The common pigeon found in most American cities is derived from a domesticated European species released in North America. As a result, the pigeons in North America have variations in coloration caused by genes previously selected by pigeon fanciers. An example is the rump, whose feathers are white in wild European pigeons but blue in many pigeons in North America. It has been hypothesized that the white rump of pigeons serves to distract predators like peregrine falcons, and therefore it may be an adaptation to reduce predation. To test this, researchers followed the fates of 203 pigeons, 101 with white rumps and 102 with blue rumps. Nine of the whiterumped birds were captured and killed by falcons, while 92 of the blue-rumped birds were killed (Palleroni et al. 2005).

a. Show the results in a frequency table. Follow the convention recommended in Chapter 2: put the explanatory variable in the columns and the response variable in the rows. What association is suggested?

b. Do the two kinds of pigeons differ in their rate of capture by falcons? Carry out an appropriate test.

c. What is the estimated odds ratio for capture of the two groups of pigeons? What is the 95% confidence interval for the odds ratio?