To see whether students who finish an exam first get the same grades as those who finish later, a professor kept track of the order in which papers were handed in. Of the first 25 papers, 10 received a ?B? or better, compared with 8 of the last 24 papers handed in. Research question: At ? = .10, is the grade independent of the order handed in? Because it is a 2 ? 2 table, try also a two-tailed, two-sample z test for ?₁ = ?₂ (see Chapter 10), and verify that z² is the same as your chi-square statistic. Which test do you prefer? Why?

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Earlier Hand-In Later Hand-In Grade Row Total "B" or better "C" or worse 11 19 17 14 31 Col Total 25 25 50