A pure birth process starting from X(O) = 0 has birth parameters (a) Write W 3 , as a sum of sojourn times and thereby deduce that the mean time is E[W 3 ] = 11/6. (b) Determine the mean of W 1 , + W...

A pure birth process starting from X(O) = 0 has birth parameters

(a) Write W₃, as a sum of sojourn times and thereby deduce that the mean time is E[W₃] = 11/6.

(b) Determine the mean of W₁, + W₂, + W₃.

(c) What is the variance of W₃,?