Let \(X_1,X_2,\ldots \) be i.i.d. mean 0, variance \(\sigma ^2\in (0,\infty )\).
(a) Use the central limit theorem as well as Kolmogorov’s 0-1 law to conclude that \(\limsup _{n\to \infty }S_n/\sqrt n=\infty \) a.s.
(b) Show that \(S_n/\sqrt n\) does not converge in probability.