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Biomedical subjects

Bruno Lecoutre

Publications and source records attributed to Bruno Lecoutre.

2 recordsLinked to original sources

Failure to construct and transfer correct representations across probability problems.

Previous studies carried out on "purely random" situations (with dice or poker chips) show the difficulties encountered by people in such situations, however simple they may be. In fact, in this type of situation, prior knowledge guides spontaneous representations, and the "errors" observed could be explained by the activation of "implicit models" which form the basis of erroneous representations. 42 statistically naïve undergraduates were given several variants of a probability problem on which errors are common. In a learning phase, subjects were given four problems involving geometric figures which were pairwise related by complementarity and equivalence relations. In a subsequent transfer phase, they were given a fifth problem involving poker chips, which was structurally isomorphic to the fourth geometric-figures problem. The findings show that people do not realize the relations between problems, and that transfer occurred only for the subset of subjects who performed correctly on the training problems of the learning phase. These results appear to have some significant implications in teaching mathematical concepts.

Adolescent↗

Assessment and monitoring in clinical trials when survival curves have distinct shapes: a Bayesian approach with Weibull modelling.

The comparison of Weibull distributions with unequal shape parameters, in the case of right censored survival data obtained from independent samples, is considered within the framework of Bayesian statistical methodology. The procedures are illustrated with the example of a mortality study where a new treatment is compared to a placebo. The posterior distributions about relevant parameters, which may provide support for a conclusion of clinical superiority of the treatment, and the predictive distributions, which may guide decision about early stopping at an interim analysis, are considered for a class of appropriate priors.

Amiodarone↗