After many years of teaching, a statistics professor computed the variance of the marks on her final exam and found it to be σ2= 250. She recently made changes to the way in which the final exam is marked and wondered whether this would result in a reduction in the variance. A random sample of this year's final exam marks are listed here. Can the professor infer at the 10% significance level that the variance has decreased? 57 92 99 73 62 64 75 70 88 60