“…The model (1) is a limiting form of zero-truncated negative binomial distribution. Negative moments of discrete distributions, mainly the binomial, Poisson and negative binomial have been investigated by various authors [Stephan [1], Grab and Savage [2], Mendenhall and Lehman [3], Govindarajulu [4,5], Tiku [6], Stancu [7], Chao and Strawderman [8], Gupta [9,10], Cressie et al [11], Cressie and Borkent [12] and Roohi [13]. Inverse ascending factorial moments have only been dealt with by Lepage [14] and Jones [15].…”