which are easily solved by the reader’s favourite method.
E. Schlemm / Statistics and Probability Letters 83 (2013) 1619–1623 1621
In the next lemma, we will investigate the function Pn : p →
n
np
p
np(1 − p)
n(1−p)
, which governs the recursion (1).
Lemma 2.2. For every positive integer n, the function Pn is convex.
Proof. We will prove the stronger claim that Pn is log-convex. An easy calculation yields