3) de la Vallee Poussin mean is Sn+1 + Sn+2 + ... + Skn (kn + 1)okn - (n+ 1)on On, k = (k - 1)n (k - 1)n where k > 1. Without loss of generality let us take k = 2 and write 2n (2n + 1)02n - (n + 1 )on = Sn + > 2n + 1 - i On ai . n n i=n+1 NO EXERCISE 1. Show that if On -> A then of > A. EXERCISE 2. Show that if lail = o(-) then ox -> A implies Sn > A