Application of Probability Statistics to a Population

Up to this point, the focus of this discussion has been on the assessment of adequacy of the diet consumed by an individual. Since a population is composed of individuals, it follows that it is possible to combine the assessments of individuals into a single population descriptor. This can be seen as the cumulative risk for the population or as the predicted prevalence of inadequate intakes in the population. The process is quite straightforward. Consider a population of ten persons that have been subjected to dietary investigation. Their usual intakes have been determined and probabilities of inadequacy have been assigned as follows Subject No. l 234 56 78 9 10 

The sum of the individual probabilities is 2.0. It is predicted that in the population of ten, two individuals would have intakes inadequate to meet their own requirements. It is not known which two individuals have inadequate intakes it is only predicted that two exist. The population risk 

Anderson et al. (1982) applied this approach to a population of children using the requirement estimates of the 1975 Canadian report (Committee for Revision of the Canadian Dietary Standard, 1975). The results are portrayed in Table VII. For comparison, the table presents also two other approaches to the interpretation of dietary intake data that are found in the literature. One is a comparison of the group mean intake to the recommended intake (this assumes that the RDNI applies to groups, not individuals). The other portrays the number of individuals with intakes below the recommended level (this assumes that the recommended intake describes the requirement of all individuals). In this perspective, the probability approach seems more logical and certainly more realistic than the other contrasting approaches. 

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