Walkabout Joker Draw (and Infective Endocarditis) Odds for Friday, March 30, 2012March 29, 2012
The Walkabout Joker Draw is now in Week 45. Friday night’s jackpot will be a rather substantial $10,638. The $638 increase in the jackpot means that the Walkabout sold 1,276 tickets last week, the same number of tickets that it sold the week before.
I learned an important lesson about odds this week. Odds are important in gambling, but they are even more important in the field of medicine.
About two weeks ago, I started having flu symptoms. At first I thought it was a hangover. Then I started getting intermittent fevers, making me wonder whether I should have taken anti-malarial pills before my trip to Bolivia last month.
After about a week of moping around the office and generally acting like a baby, I finally went to see my doctor. Of course, when his nurse took my temperature, it was 98.6 degrees. I nonetheless whined to him about my flu symptoms and intermittent fevers. He sent me off to have blood cultures drawn to check for infection.
Two days later, I woke up feeling pretty good, ate breakfast, and watched the last part of the Spurs-Chelsea match. Then I got a call from my doctor. On a Saturday. At 8:15 a.m. That’s never good. “You’ve got bacteria in your blood. You should go to the hospital in the next two hours and I’ll have you admitted.”
I told him I was planning to get a haircut, and I asked him I could do that first and then go the hospital. He said yes. Which is good, because I wanted to look totally hot for all the nurses.
At the hospital, the doctors hooked me up to IV antibiotics and told me that I probably had infective endocarditis. That’s an infection of the heart valves which strikes about 1 in 25,000 people every year. I knew I was at a higher risk of getting it because I have always had an underlying asymptomatic heart valve abnormality.
Anyway, once they told me the name of what I had, I did what any degenerate gambler would do. I pulled out my phone and started looking up the odds that I was going to die. Then I started googling all the hospital doctors’ credentials. That’s totally normal.
Most of the websites cite a 15-20 percent mortality rate for the disease. According the totally authoritative Wikipedia page on infective endocarditis, the chance of dying from it is precisely 18 percent. I prefer to think of that as an 82 percent chance of living. That’s comforting. 82 percent.
That’s like a Michael Jordan free throw.
Of course, because I’m relatively young and had only mild symptoms, I knew that my odds of recovery were much better. I later learned that the specific type of bacteria in my blood only causes death in about 2% of endocarditis cases. So I estimated that I actually had about a 98% chance of living. Then I reduced that down to 97% when I realized that none of my doctors were Jewish.
I’m now on my fifth day in the hospital getting IV antibiotics, even though I feel perfectly fine. I should get out of here in the next day or two, then I’m looking at 4-6 weeks of daily IV antibiotics at home. I’ll probably finish the antibiotic course in early May, just in time for my next trip to filthy, germ-filled Cambodia. Where at least they always wipe the beer can tops with those little tissues.
Speaking of beer and germs, let’s get back to discussing the Walkabout. I’ll estimate that the Walkabout sells 1,400 Joker Draw tickets this week, after selling 1,276 tickets in each of the prior two weeks. There are currently nine face down cards remaining, including the winning Joker. That means that buying a single $1 ticket will give you a 1 in 1,400 x 1 in 9 = 1 in 12,600 chance of winning the $10,638 jackpot.
There are still two Aces remaining, so your ticket also gives you a 1 in 6,300 chance at winning an $800 moto. So, the overall “expected return” on a $1 purchased ticket will be about 97 cents, assuming 1,400 tickets in the drum. That’s a pretty good wager.
Regardless of the number of tickets sold, we know that the lucky patron whose ticket is called will have a 1 in 9 chance of turning over the Joker and winning $10,638. That chance alone is “worth” $1,182. The additional 2 in 9 chance of winning $800 is worth $178.
This means that the called ticket will be “worth” $1,360 before the ticket holder turns over his or her card. If you can buy that ticket from an impoverished hooker or English teacher for $1,000, you’ll make an immediate 36% return on your investment. Of course, there will still be a 2 out of 3 chance that you’ll turn over a worthless card and win nothing at all. Good luck.