Abstract
The JIS diagnostic audiometer is generally used to obtain the mean hearing threshold levels (MHTL), for physically handicapped persons and workers in noisy environment based on the laws concerning welfare services and accidental compensation.
Hearing threshold level values obtained by an audiometer are represented only as a set of numbers obtained by multiplying 5dB by integers. HOW-ever, these numbers are discrete and not continuous. Therefore, another set of MHTL given by the calculation called the one fourth or one sixth method by the law in Japan should be consisted of numbers also obtained by multiplying 5dB by integers.
From calculation by mathematical binary scale, we can obtain a MHTL which contains no decimal numbers or numbers not wholly divisible by 5dB. Furthermore, the recongnition of the presently used grades far compensation coincides completely with the grade approved by the formerly used calculation which I believe is unreasonable and meaningless.
