Errors and discrepancies in measurement of tooth size

The purpose of this study was to evaluate the experimental errors and discrepancies involved in the measurement of tooth size using plaster casts. The terminology em-ployed is taken principally from Beers, ' who defines the terms used in this area as follows: A. Error. This word is used correctly with two different meanings: 1. To denote the difference between a measured value and the "true " value. Except in a few trivial cases, the "true " value is unknown and the magnitude of the error is hypo-thetical. 2. When a number such as (±.087) is given or implied, "error " refers to the estimated uncertainty in an experiment and is expressed in terms of such quantities as standard de-viation, average deviation, probable error, or precision index. B. Discrepancy. This is the difference between two measured values of a quantity, such as the difference between two measured values of the same quantity obtained by two investigators. The word "error " is often used incorrectly to refer to such differences. C. Experimental errors. When a given measurement is repeated, the resulting values, in gen