Abstract: The beta-binomial model is combined with a Thurstonian psychometric function to obtain estimates of the parameters of a distribution applicable to replicated difference tests. A method of estimating the variance of d' obtained from these tests is provided. A formula for determining sample size, which is composed of the number of trials (or...
Abstract: Binomial tests are commonly used in sensory difference and preference testing under the assumptions that choices are independent and choice probabilities do not vary from trial to trial. This paper addresses violations of the latter assumption (often referred to as overdispersion) and accounts for variation in inter-trial choice probabilities following the Beta distribution....
Abstract: A sensory threshold can be defined generally as a stimulus intensity that produces a response in half of the trials. The definition of the population threshold is discussed. Five main classical statistical procedures for estimating thresholds are reviewed. They are the probit, the logistic, the Spearman-Karber, the moving average and the up-and-down procedures....
Abstract: In his Nobel lecture on the development of the beta-antagonists and antihistamines, Black (1989) emphasized the importance of pharmacokinetic models in providing direction for his research. "Models...are not meant to be descriptions, pathetic descriptions of nature." he said. "They are designated to be accurate descriptions of our pathetic thinking about nature." Science is...
Abstract: Variants of the method of tetrads are discussed and their psychometric functions are both derived and presented in table form. For the first variant, the Unspecified method, subject response is correct provided that the subject, when presented with two stimuli form one set and two stimuli from a second set, correctly segregates the...
Abstract: Using a Rank-Rating method, d' values were obtained for stimuli from a model system using 15-point, 9-point, 7-point and 5-point category scales. For an apple/grape juice system, d' values were compared for 9-point and 7-point scales. There was general agreement on d' values among the scales, except where stimuli had their scores 'bunched'...
Abstract: Same-different, duo-trio and triangle discrimination methods were compared using vanilla flavored yogurt with and without added sugar as the medium. Two experiments were performed, one in controlled laboratory conditions and the other in conditions approximating more to consumer testing. A modification of the same-different test had greater power than the duo-trio of triangle...