November 17, 2017

# Lotto

Q: Can I improve my chances of winning Lotto by…

A: No.

Q: But….

A: No.

Q: …

A: Just no.

Q: … by buying a ticket?

A: Ok, yes. But not by very much.

Q: You sound like you’ve been asked about Lotto odds a lot.

A: There’s a larger-than-usual jackpot in the NZ Powerball

Q: Enough to make it worth buying a ticket?

A: If you like playing lotto, sure.

Q: No, as an investment.

A: I refer the honourable gentleman to the answer given some moments ago

Q: Huh?

A: No.

Q: But \$35 million. And a 1 in 38 million chance of winning. And 80c tickets.  Buying all the tickets would cost less than \$30 million. So, positive expected return.

A: If you were the only person playing

Q: And if I’m not?

A: Then you might have to share the prize

Q: How many other people will be playing?

A: Lotto NZ says they expect to sell more than a million tickets

Q: Compared to 38 million possibilities that doesn’t sound much

A: That’s tickets. Not lines.

Q: Ah. How many lines?

A: They don’t say.

Q: Couldn’t the media report that instead of bogus claims about a chemist in Hawkes Bay selling better tickets?

A: Probably not. I don’t think Lotto NZ tells them.

Q: That story says it would take 900 years to earn the money at minimum wage. How long to get it by playing Powerball?

A: At, say, ten lines twice per week?

Q: Sure.

A: 36900 years.

Thomas Lumley (@tslumley) is Professor of Biostatistics at the University of Auckland. His research interests include semiparametric models, survey sampling, statistical computing, foundations of statistics, and whatever methodological problems his medical collaborators come up with. He also blogs at Biased and Inefficient