Describing time to response

Abstract

As can be judged from the examples of earlier chapters, in statistical papers it is quite usual for quantal assay data to be presented without any mention being made of the duration of the experiment. However, we note for example that the data of Table 2.1 were collected 1 hour after exposure to the chemical, and the data of Table 1.14 were obtained 96 hours after treatment. When times are cited, multiples of 24 hours are quite usual, as is the 7-day assay. For instance, Sprague (1970) mentions 48- and 96-hour ED ₅₀ assays. Notation such as ED ω/μ is sometimes encountered, signifying the dose expected to affect ω% of individuals in μ time units (e.g. McLeish and Tosh, 1990; Carter and Hubert, 1984).