Parametric analysis of sojourn times in conditioned place preference experiments.
In conditioned place preference experiments, groups of animals are typically compared by means of the total time spent in a treatment environment. The total times are often positively skewed, which prohibits the use of parametric procedures that require normal distributions. Common response time models for such total times are also inadequate because the fit of the models to the data is often poor. The present paper assumes that the sojourn times of a single animal are independent and that they all follow the same 1-parameter exponential model. The exponential parameter allows a number of simple interpretations. We propose point estimates, confidence intervals, a goodness-of-fit test, and a test for comparing 2 samples. The procedures are also applied to single animals, and a test is given for comparing the animals of a group. The kind of parametric analysis suggested enables better interpretation than does the simple distribution-free comparison of 2 groups based on the total time spent in the treatment environment.
Krauth
J
J
Institute of Psychology, University of Düsseldorf, Germany.
D000818:Animals; D001522:Behavior, Animal; D003216:Conditioning, Operant; D008960:Models, Psychological; D013223:Statistics as Topic