Exercise 13.3.9 To see the plausibility of Eq. (13.14), take the expectation of its left-hand side and drop limn→∞ to obtain 2

n−1 k=0 E



X



(k+1) t 2n



− X



kt 2n

2

.

Show that the preceding expression has the value μ2t22−n +σ2t, which approaches

σ2t as n→∞.