E) Structure of the rules

1) Rules were usually too complex to analyze by hand but those that were understandable had extrapolative features.


2) The 55th best $/DM rule over the selection period, whose excess return was 7.34, number of trades was 37 and correlation with the median rule was 0.9911, prescribed: "Take a long position if the four-day minimum of the normalized exchange rate is greater than one."

F) Rules trained on $/DM data proved profitable on other exchange rates, out of sample.