My wife just called and said that, by chance, she decided to go home for lunch to walk the dog and the Fedex truck pulled up. I guess that ends this little experiment. Roll credits...
The probability of the sub running into my wife exactly on the 5th try: 8.2%
The probability of it happening within the first 5 attempts: 67%
Number of attempts it would take to get above 95% probability of successful lunch-time delivery: 15
Expected value E(x), number of attempts before delivery is expected: 5
Number of people who normally go home for lunch in the DC area: about 0
Typical commute, DC area: 1.5 hours
Having a new sub to setup when I get home: PRICELESS.