Testing for Variance: The fan blades upon commercial jet engines should be replaced when wear on such parts indicates too much variability to pass inspection. A large engine haves thousands of fan blades, and safety regulation requires that variability measurements on the population of all blades not exceed 0.18 mm2. An engine inspector took a random sample of 61 fans blades from an engine with a sample variance 0.27 mm2. Using a 0.01 level of significance, is the inspector justified in claiming that all the engine fan blades must be replaced?
Find the value of the chi-squared statistic, ?2.