THE ASYMPTOTIC APPROACH TO BEHRENS'S INTEGRAL, WITH FURTHER TABLES FOR THE d TEST OF SIGNIFICANCE

To the present generation of statisticians, familiar with ' Student's ' distribution and with the process of 'Studentizing' unknown parameters, it has for some time appeared to be a somewhat puzzling historical fact that this advance in simple statistical procedure was not made long before, and was not made rather by a mathematician than by a research chemist. Light is perhaps thrown on this puzzle by the contrast, which has been striking during the last twenty years, between the facility, confidence and skill with which the new tests have been applied by practical men in research departments, and the embarrassment and confusion of many discussions, in journals devoted to mathematical statistics, by mathematically minded authors lacking contact with practical research.