A certain scientific theory supposes that mistakes in cell division occur according to a poisson process with rate 2.5 per year, and that an individual dies when 196 such mistakes have occurred. assuming this theory, find

(a) The mean lifetime of an individual

Rate = 2.5 age it dies = 196 E [Xi] (which we need to compute for the year) is equal to 196 (0.4) = 78.4 years

(b) The variance of the lifetime off an individual

Rate=2.5 age it dies = 1[Xi] (which is needed to compute the variance) is equal to 196 (0.16) = 31.36 years.