Fig. 2

Average width and coverage probability of selected gamma CIs for age-adjusted mortality rates: simulation scenario 2. Average CI width and coverage probability of the Anderson–Rosenberg, Tiwari, Fay–Kim, and Fay–Feuer gamma CIs is based on 500 simulations with 10,000 replications each for age-adjusted mortality rates R = ∑(w_i/P_i) D_i and is presented as a function of the coefficient of variation (CV) of the weights u_i = w_i/p_i. The weights u_i and age-specific probabilities of death were drawn at random from the uniform distribution on the unit interval, and a multinomial distribution was used to generate the D_i conditional on the total D = ∑D_i. In the top row, D was generated from a Poisson distribution with mean 20, whereas a mean of 10 was used in the bottom row. For the latter, a truncated Poisson distribution was used in simulations to ensure D remained ≥ 10