 Solution

ID: past-exam-of-the-mathematics-course-of-the-year-1-of-the-natural-sciences-course-of-the-university-of-cambridge/2016/paper-2/16/a/iii/solution

The interval within one standard deviation is

[3/5, 9/5]

. Of the possible integer outcomes

0, 1, 2

, only

1

lies in this interval. Hence

P (∣ X - μ ∣ \leq σ) = P (X = 1) = \frac{3}{5} .

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