Computation of the Median Age of Eruption of Permanent Teeth Using Probit Analysis and an Electronic Computer

¹ Department of Preventive Dentistry, Faculty of Dentistry, University of Sydney, N.S.W., Australia

In this paper the use of the arithmetic mean and the median have been reviewed, stressing the suitability of the median for tooth eruption data analysis. Graphical, arithmetic, and probit procedures for estimation of the median have been contrasted, and the use of probit analysis in eruption surveys utilizing an electronic computer has been discussed. Modifications necessary for the successful use of a standard probit analysis procedure with a computer are given.

A study on the age of eruption of the permanent teeth of 5,660 New South Wales school children, aged 6 to 15 years inclusive, has been used as a practical example to show how data, which does not completely cover the expected range of the ages of eruption of the teeth of the population, may be successfully analysed with an electronic.