(b) A certain computer simulation generates a random amount of data whenever it runs. On average it creates 30Mb of data, with a standard deviation of 5Mb. The simulation is run 64 times. Let D be the random variable for the total amount of data generated.
(i) Find E(D)
(ii) Find Var(D)
(iii) Using a normal approximation, estimate the probability that the data will overflow the computer’s 2000Mb storage disc.

Question

(b)	A certain computer simulation generates a random amount of data whenever it runs. On average it creates 30Mb of data, with a standard deviation of 5Mb. The simulation is run 64 times. Let D be the random variable for the total amount of data generated.
(i)	Find E(D)
(ii)	Find Var(D)
(iii)	Using a normal approximation, estimate the probability that the data will overflow the computer’s 2000Mb storage disc.

anonymous · Answer

(i) E(D)=nu=64*30=1920
(ii)Var(D)=n σ^2=64*5^2=64*25=1600
I don't know how  to find part (iii)