Date: 2010-10-04 09:21:00
bad math: pet ownership and lottery winners

A headline in the local paper this morning reads Lucky Lotto winnners like cats with the first two paragraphs:

HAVING A cat could improve your chances of winning Lotto - by a whisker.
A survey released today by New Zealand Lotteries shows 39 percent of big Lotto winners have cats, making felines the most popular pets among lucky Lotto winners. Dogs are second but way behind with only 27 percent of big winners preferring man's best friend to moggies.

My first reaction upon reading that was, "so what?". Surely the pet ownership statistics among the general population would be reflected in those statistics for the small number of lotto winners. The New Zealand Petfood Manufacturers Assocation claims the ownership numbers for New Zealand as a whole are 53% for cats and 35% for dogs.

What does this tell us? These numbers show that a greater proportion of non-pet owners win the lottery than there are non-pet-owners in the general population. Having a cat certainly doesn't "improve your chances" as the article claims. (These are just rough numbers because we don't know what proportion of either the general population or lottery winners own both a cat and a dog.)

They say the lottery is a tax on people who are bad at math. Apparently, the "bad at math" part extends to those writing about the lottery, too.

Greg Hewgill <greg@hewgill.com>