The Multi-State Lottery Association’s Strange Math
The Powerball jackpot is huge. I used my trusty PHP Powerball Picker to generate 5 picks for tonights drawing for $310 million dollars. Shortly after 9:00 MST I went to the Powerball web site to check the results. in one of my picks I got 2 of the 5 main numbers, but not the Powerball. I went to the “Prizes and Odds” page to see if that was worth anything. I found this chart:

I don’t have a math degree… but this just doesn’t look right. The easiest one to spot is at the bottom of the chart. The odds of getting just the powerball number correct. The value of the Powerball will always be an integer of 1–42. They show the Odds of that prize as 1:69. I don’t get it. It seems wrong. I can guarantee you that I can win that prize if I spend $42. So how do the odds end up as 1 in 69? I found this page which shows the odds more specifically as 1:68.96. I still think it’s wrong. If I am assured to win that prize playing 42 times I think the odds should be 1:42… of course this ignores the 5 white balls, but hey— I’m after my $3.
By the way, in one of my 5 picks I got 2 of the 5 white balls. My shitty math figures that is a 1:148.5 chance of matching 2, but I’m sure that’s not how the Multi-State Lottery Association would calculate it.