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# Stats urgent help watch

1. 5. Serious delays on a certain railway line occur at random, at an average rate of one per week.
a. Show that the probability of at least four serious delays occurring during a particular 4-week period is 0.567, correct to 3 decimal places.
b. Taking a year to consist of thirteen 4-week periods, find the probability that, in a particular year, there are at least ten of these 4-week periods during which at least 4 serious delays occur.
Given the probability of at least one serious delay occurring in a period of n weeks is greater than 0.995, find the least possible integer value of n
i did the first part, how do i do part ii?
2. I got 0.1144 for the second part, is this correct?

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