Quantiles of the filtered chest radiograph distribution attributable to an anthrax outbreak. Plots of the day-by-day quantiles of the filtered radiograph counts attributable to an anthrax attack, based on 500 simulated anthrax outbreaks. The filtering operation, as defined by (3), is based on the first ten months of training data from Akron, in combination with one of four filters (1-day, 7-day, linear and exponential). Each filtered signal is scaled by τ
k, 0.03, calculated using a normal approximation, for comparisons to be made across filters.