Manufacturing and Product Development
In January 2013, flaws were discovered in two Boeing 787 Dreamliners aircraft. Japan Airlines found cracks in the cockpit window in one jet and a minor oil leak in another.18 To assure the public that the jet is safe, the FAA selected 20 Dreamliners currently operated by American Airlines and carefully inspected each for any flaws.
a. Is this an observational or an experimental study? b. What is the variable of interest?
c. Is this sample random? If so, justify your answer. If not, describe a technique to obtain a random sample.