Instruments

eight formulas, taken apart

Fame is the wrong sort key. These are the formulas you meet in papers and in decisions — or the ones that are famous precisely because they are misread.

Preview — checked, not finished

8 of 8 built

1. 1

   The test that is 99% right

   Bayes' theorem, and what a positive result actually means

2. 2

   The curve that is always steeper than it looks

   Exponential growth and decay, and the log axis that makes it visible

3. 3

   What a ticket is worth

   Expected value, and why a good bet can still be a bad decision

4. 4

   Why averages behave

   The central limit theorem, and the error bar you did not ask for

5. 5

   The jinx that isn't

   Regression to the mean

6. 6

   The number that is not a probability

   The p-value, and the four things it does not tell you

7. 7

   A square wave is a pile of sines

   The Fourier series

8. 8

   How far is it, really

   The norm and the dot product