This short case describes a famous experiment conducted by Sir Ronald A. Fisher and colleagues to test Dr. B. Muriel Bristol's claim that she could tell "only by tasting" whether milk or tea was poured first into her cup. Using hypothesis testing, students must answer the question of how many correct picks the lady tasting tea (LTT) must make in order to "prove" her claim.This case will become an "exercise" when such an option exists--mainly for pricing purposes. In the meantime, it will be internal use only.ExcerptUVA-QA-0771Aug. 31, 2011The Lady Tasting TeaThe photo to the right is of R. A. Fisher (1890–1962), who was one of the founders of modern statistics. In 1919, Fisher had begun working at Rothamsted Experimental Station, an agricultural research institution in England. The following is an account of what has become a famous event in the history of the development of statistics:Already, quite soon after [Fisher] had come to Rothamsted, his presence had transformed one commonplace tea time to [a] historic event. It happened one afternoon when he drew a cup of tea from the urn and offered it to the lady beside him, Dr. B. Muriel Bristol, an algologist [one who studies algae]. She declined it, stating that she preferred a cup into which the milk had been poured first. "Nonsense," returned Fisher, smiling, "Surely it makes no difference." But she maintained, with emphasis, that of course it did. From just behind, a voice suggested, "Let's test her." It was William Roach, who was not long afterward to marry Miss Bristol. Immediately, they embarked on the preliminaries of the experiment, Roach assisting with the cups and exulting that Miss Bristol divined correctly more than enough of those cups into which tea had been poured first to prove her case.Miss Bristol's personal triumph was never recorded, and perhaps Fisher was not satisfied at that moment with the extempore experimental procedure. One can be sure, however, that even as he conceived and carried out the experiment beside the trestle table, and the onlookers, no doubt, took sides as to its outcome, he was thinking through the questions it raised: How many cups should be used in the test? Should they be paired? In what order should the cups be presented? What should be done about chance variations in the temperature, sweetness, and so on? What conclusion could be drawn from a perfect score or from one with one or more errors?This event is also discussed in chapter 1 of the book The Lady Tasting Tea: How Statistics Revolutionized Science in the Twentieth Century.For the purposes of our discussion, assume the experiment will consist of 10 pairs of cups (each pair comprising one cup with milk poured before tea and the other with tea poured before milk) for which Dr. B. Muriel Bristol, the algologist, will be asked to determine whether milk or tea was poured first
