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Population Thresholds

Ennis, D. M. (2000). IFPress, 3(2) 2-3.



A surprising number of applied sensory problems can be classified as threshold problems. For example, the time after application when an air freshener can no longer be detected is a time threshold. Similarly, the moment at which an off-note can be detected in a food product is a threshold. This information can be used to establish the shelf-life of the product. Methods for measuring thresholds have been developed for individuals, but in many applications there is more interest in population thresholds than individual thresholds. Special problems arise when extending the ideas of individual thresholds to population thresholds. This report overviews a new approach to measuring population thresholds.


Figure 1. Beta distribution of response proportions across individuals at a particular dosage.

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