Standard deviation
In: 4
Think about these two statements:
1. The average human has approximately two legs.
2. The average human is approximately 30.
Clearly, the first statement describes the average human much better, this is because the standard deviation of the distribution of the number of legs is extremely small. That is, the average is 2 because pretty much everybody has 2 legs, except some very small portion of the population.
The second statement is a bit silly, sure, the average age on Earth is about 30, but if you walk down the street you’ll see people of all different ages, and knowing the average by itself doesn’t tell you much about the population. This distribution has a much higher standard deviation.
Standard deviation measures how far from the average the actual numbers in a distribution are, on average. It’s literally the average of the squared difference of a random variable and its average.
Latest Answers