안녕하세요 이연욱 샘입니다.
13 C 문제에서 만약 find the probability that Joshua arrives at his office by 9 am exactly three days during the five consecutive days 이라고 한다면 binompdf (5, 0.631, 3) 가 정답입니다.
하지만 Exercise 13 C 문제에서는 find the probability that Joshua arrives at his office by 9 am exactly three consecutive days during the five consecutive days 이라고 했기 때문에
binompdf (5, 0.631, 3) 는 틀린 답이 됩니다.
Three consecutive days를 casework을 통해서 분리해서 probability를 구해야 정답을 구할 수 있습니다.
Case 1: three consecutive days (1st, 2nd, and 3rd days)
Case 2: three consecutive days (2nd, 3rd, and 4th days)
Case 3 three consecutive days (3rd,, 4th and 5th days)
질문에 도움이 되었으면 합니다. 감사합니다.