What? Why!?

Have you ever heard of the 50/50/90 rule? It goes in tandem with Murphy's law, only this one states that, whenever you have a 50/50 percent chance of getting something right or not, 90% of the time you get it wrong. Being applied to simple economics (which, perhaps this is only happening because my high school was stripped of this course, ergo, I'm not able to take it), specificially the exchange rate between the USD and EUR, this seems to apply to my expectations. Last week, when the stock market was on the rise, closing higher by hundreds of points each day, one would expect the exchange rate to improve between the two currencies, in favor of the US Dollar, right? Obviously not, as it plummeted to a (for me) all-time low, at only 77.4 cents to one USD. When I went to Europe in 2004, the exchange rate was 80 cents to one dollar, and I watched it peak at 83 centers per dollar in summer 2005. Now, as the stock market is crashing, I see the exchange rate has actually improved! How exactly does this make sense? I mean, in a world filled with backwardness and nought, I guess it does make perfect sense to dish the opposite of one's expectations, usually to the dismay of the querier, however, in this specific case, I'm pleased that the exchange rate has risen to 78.2 cents, and can only pray that it will continue to improve until I decide it is time to cash in my greenbacks for some rainbow-colored Euro-cash.