Solution

ID: past-exam-of-the-mathematics-course-of-the-university-of-cambridge/2024/ib/paper-1/18h/d/solution

The two tests have the same size, but their powers cross. At ,
At ,
Thus Test 2 is a same-size test that beats Test 1 at one alternative, while Test 1 beats Test 2 at another. By the crossing-power obstruction to a uniformly most powerful test,

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