In the last exercise you saw that Lebron James was
0.55 standard deviations above the mean of NBA player heights. He’s taller than average, but compared to the other NBA players, he’s not absurdly tall.
However, compared to the OkCupid dating pool, he is extremely rare! He’s almost three full standard deviations above the mean. You’d expect only about
0.15% of people on OkCupid to be more than 3 standard deviations away from the mean.
This is the power of standard deviation. By taking the square root of the variance, the standard deviation gives you a statistic about spread that can be easily interpreted and compared to the mean.
We’ve created a visualization that shows the mean, first, second, and third standard deviations of each dataset.
Compare your height (in inches) to the heights of NBA players and OkCupid daters.
You’re likely below the first standard deviation for the NBA. Are you below the second? How unusual is your height compared to the OkCupid members?