LOG-NORMALITY OF DISTRIBUTION OF OCCUPATIONAL EXPOSURE CONCENTRATIONSTO COBALT

In evaluating occupational exposures, the daily exposure levels of a w orker are generally assumed to be distributed log-normally between day s. When there are many workers in a job group, the individual worker's arithmetic means are assumed to be distributed log-normally. Using th e cobalt exposure data in a hard metal factory, these assumptions were examined with the Shapiro-Wilk W test. The hypothesis of log-normalit y was accepted in all cases, while the hypothesis of normality was rej ected in some cases. (C) 1997 British Occupational Hygiene Society.