Solution

ID: past-exam-of-the-mathematics-course-of-the-university-of-cambridge/2004/iii/paper-38/5/e/solution

Let indicate a point outside its pointwise 95% limits. Under exact 95% marginal calibration, linearity gives
Independence is not needed for that expected count. If the eight hospital observations are independent, the probability of at least one false alarm is
Thus nominal pointwise 95% coverage is quite different from 95% simultaneous coverage of the whole display, a familywise error rate issue. Without independence, the product formula need not hold; the union bound is at most .
Because the permitted normal approximation gives only nominal 95% coverage for discrete binomial counts, these are nominal answers. With exact outside probabilities , the exact expected count is and, under independence, the exact probability is .

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