Accounting for Uncertainty When Estimating Counts Through an Average Rounded to the Nearest Integer
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In practice, the use of rounding is ubiquitous. Although researchers have looked at the implications of rounding continuous random variables, rounding may be applied to functions of discrete random variables as well. For example, to infer on suicide difference between two time periods, authorities may provide a rounded average of deaths for each period. Suicide rates tend to be relatively low around the world and such rounding may seriously affect inference on the change of suicide rate. In this paper, we study the scenario when a rounded to nearest integer average is used to estimate a non-negative discrete random variable. Specifically, our interest is in drawing inference on a parameter from the pmf of Y, when we get U=n[Y/n]as a proxy for Y. The probability generating function of U, E(U), and Var(U) capture the effect of the coarsening of the support of Y. Also, moments and estimators of distribution parameters are explored for some special cases. Under certain conditions, there is little impact from rounding. However, we also find scenarios where rounding can significantly affect statistical inference as demonstrated in two applications. The simple methods we propose are able to partially counter rounding error effects.
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