LOGNORMAL APPROXIMATION TO PRODUCTS AND QUOTIENTS
Simon Broadbent · Biometrika · 1956
Measurements have been made which are subject to error, and we are required to give limits to a combination of the values measured. The combinations considered here are products and quotients. Some exact results are available in simple cases, but otherwise an approximation is required. The lognormal distribution, which is asymptotically exact, is shown to give useful approximations when fitted by moments to the combination. This method of fitting is nearly optimum in a defined metric. Tables are given which make its application simple.