It was desired to equip our study so that the variables of interest can be determined within a coefficient of variation (CV) of 25%, with 90% confidence. Sixty subjects would yield estimates of the mean level of 8 of the 9 study variables to within a CV of 25%, with 90% confidence. The one exception is the highly variable 8-isoprostane measure, whose mean level could be estimated to within a CV of 37%, with 90% confidence.