9. Let’s assume that an aviation researcher hypothesized that the proportion of runway incursions would be uniform across four different runway incursion categories: (a)

those attributed to air traffic control (OE/OD/OI),

(b) those attributed to pilots (PD), (c)

those attributed to vehicles and pedestrians (V/PD), and

(d) those that were classified as “other” or “unknown” (OTH/UNK). Let’s further assume that a 10-year analysis of runway incursions from the FAA database resulted in sample sizes of N = 2990, 98644, 3507, and 773, respectively, for the four categories, and the results of data analysis were χ2(3, α = .05) = 10638.95, p < .0001. What can you conclude?

a. There is a significant difference in the proportion of frequencies of runway incursions across the four categories.

b. The sample data are consistent with the researcher’s hypothesis.

c. The results are flawed because the proportion of frequencies are heavily biased toward pilots.

d. There must be an error in the calculation of χ2 because χ2 cannot be that large.