Scenario: Open the FAA Bird Strikes CA data table, which contains data from three airports in California: Los Angeles, Sacramento, and San Francisco. For each question below, we want to know if the attributes in question varied by location (that is, is the response variable independent of airport?). Conduct a test of independence and report on your conclusions, explaining the reasoning for your conclusion. For all tests, use a significance level of 0.05.

a. Wildlife strikes occur during different phases of flights. Does the frequency of strikes in each phase vary by airport? (NOTE: You should recode the PHASE_OF_FLT column as we did in Chapter 4.)

b. Does the airline operator involved in the incident vary by airport? Be sure to check for sample size conditions before drawing a conclusion.

c. BIRDS_STRUCK is an ordinal variable describing the number of birds struck during the flight. Is this variable independent of the airport?

d. Does the size of the bird(s) struck (SIZE) vary by airport?