Musings on everyday probability
Right now, in the US, deaths from COVID-19 are still increasing at an exponential rate. This means they double every few days. A shutdown in other countries, like we have in NY, quickly curbed infections -- that is the only explanation for the end of exponential growth in China, and now in Italy.
Our NYC mayor is freaking out because of the dramatic increase in cases. He's wrong.
The current death rate in the U.S. for the coronavirus is more than 4%. But it's way too high, and that's bad news.
The evidence that showing vaccines are safe and that they save lives is generally overwhelming, so I'm always pleased to see another article reviewing the data behind them. I figure such articles will lead to even more people being vaccinated and more lives saved.
However, I was disappointed that a recent New York Times article did the statistics so poorly. The article compares 10,000 people who got various diseases with 10,000 people who were vaccinated. This comparison is inappropriate, because most people who do not get vaccinated do not get the disease they are being vaccinated for, and, especially for diseases like the flu, many people who do get vaccinated get the disease they were vaccinated for. A proper comparison would compare some number of people who were vaccinated against the same number who were not vaccinated.
Lesson 2: The Made-up Probability
My prior discussion regards improperly multiplying probabilities when using statistics in court. But what about when someone simply makes up the probabilities? Surely, that wouldn’t happen in a court of law would it?
This is the first in two blogs regarding incorrect use of statistics in court.
The chances that a randomly selected man will be 7 feet tall or more is about one in a million. So it follows that the chance of two randomly selected men being 7 footers is the square of one in a million, which is one in a trillion, right?
An article and accompanying graph in the New York Times claims that low-skilled workers are not gaining the advantage they once were by moving to big cities. But it misses something important, calling the whole claim into question.
In the third quarter of the NBA Eastern Conference Finals last week, Boston missed all 14 3-pointers they attempted. This led the announcer to say something like, "by the law of averages, they are bound to improve." But will they?