A measure of goodness-of-fit for the lognormal model applied to occupational exposures.
Waters-MA; Selvin-S; Rappaport-SM
Am Ind Hyg Assoc J 1991 Nov; 52(11):493-502
A new method was presented to help in the evaluation of the goodness of fit to the log normal model that is a simple extension of calculations made routinely by occupational hygienists. This new measure, the ratio metric compares the ratio of two estimators of the mean, the direct estimate of the mean and the maximum likelihood estimate of the mean of a lognormal distribution. The ratio metric gave results which were compared to probability plotting and to two traditional measures of goodness of fit, the Lilliefors test and the W-test. The results of the ratio and W-tests were comparable for a variety of occupational exposure data, but the Lilliefors test was overly conservative and did not detect several cases of gross deviations from lognormality. Results indicated that the ratio metric is an effective alternative to the Lilliefors test and is easier to perform than the W-test for the range of data usually encountered by occupational hygienists.
NIOSH-Author; Statistical-analysis; Occupational-exposure; Epidemiology; Exposure-levels; Industrial-hygiene; Industrial-exposures
American Industrial Hygiene Association Journal