Testing the means
•Use observed lognormal distribution.
•Natural logs of Sb in the five samples are 6.73, 6.68, 6,40, 6.43, 6,46. •Means and standard deviations of the two groups are 6.71±0.04 and 6.43±0.03. •Two-sided p < 0.0028. (< 1/360 chance that the means are the same)