6.7 Airline flight delays. Here are the numbers of flights on time and delayed fortwo

Chapter 0, Problem 6.7

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6.7 Airline flight delays. Here are the numbers of flights on time and delayed fortwo airlines at five airports in one month. Overall on-time percents for eachairline are often reported in the news. The airport that flights serve is a lurkingvariable that can make such reports misleading.6Alaska Airlines America WestOn time Delayed On time DelayedLos Angeles 497 62 694 117Phoenix 221 12 4840 415San Diego 212 20 383 65San Francisco 503 102 320 129Seattle 1841 305 201 61(a) What percent of all Alaska Airlines flights were delayed? What percent of allAmerica West flights were delayed? These are the numbers usually reported.(b) Now find the percent of delayed flights for Alaska Airlines at each of the fiveairports. Do the same for America West.(c) America West did worse at every one of the five airports, yet did better overall.That sounds impossible. Explain carefully, referring to the data, how this canhappen. (The weather in Phoenix and Seattle lies behind this example ofSimpsons paradox.)