Assume that the monthly worldwide average number of airplaine crashes of commercial airlines is 2.2. ?

What is the probability that there will be

(a) more than 4 such accidents in the next month?

(b) less than 2 such accidents in the next 3 months?

(c) exactly 7 such accidents in the next 5 months?

1 Answer

  • rotchm
    Lv 7
    1 year ago

    Assuming a Poisson distribution, since u did not specify which distribution you are using.  

    P(k) = a^k * e^(-a)/k! where a =  the avg # events per time interval.

    a) a=2.2. You want P(5) + P(6) + P(7) + ... = [left for you]. Hint: Use complement. 

    b) View it as a Poisson distrib with a = 3*2.2 = 6.6 events per 3 mo.

    You want P(0) + P(1) + P(2). 

    c) View it as a = 5*2.2 events per 5 mo. You want P(7).

    Show ur computations & answers & we can verify them for you.


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