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7. (15 points) To test two methods of instruction, 50 students are selected at random from each of two groups. At the end of the instruction period, each student is assigned a grade (A, B, C, D, or F) by an evaluating team. The data are recorded as follows: Grade A B C D F Totals GROUP I 7 13 16 11 3 50 GROUP II 4 9 19 16 2 50 (i) Derive a significance level-a = 0.05 critical region for testing the following complement tary hypothesese: Ho : The two groups have the same distribution, H1 : not Ho. (24) (You may use Pearson's theorem.) (ii) Discuss whether the critical region you obtained above gives type I error exactly or ap- proximately 0.05. If you think it is the former, justify; Otherwise, state possible as- sumptions that would make the approximation more accurate. (iii) Execute your hypothesis testing for the data given above. State your conclusion and also a non-statistical interpretation