Control curves for extreme value methods

A method is presented for the calculation of control curves for the Modified Gumbel analysis of extreme values. For each plotted extreme value an upper bound, a lower bound and an ‘inclusion’ probability p are defined such that for each and every point, the probability of it plotting within the upper and lower bounds is equal to p. The loci of the upper and lower bounds then form the control curves. A rationale for the appropriate choice of p, based on Binomial Probability is also presented. Similar procedures are also presented for Cookʹs Method of Independent Storms.