Average Mean types

There are two symbols in math that are often used to denote the mean. σ, the lowercase greek letter sigma, refers to the population mean. This is the average for an entire population - all of the possible values. The average of all the grades on a particular test is an example.

x̄, pronounced x-bar, refers to the sample mean. This is the average of a sample of values from the total population. You might take a random sample of people across the country to find the average height of the population, but it's impractical to measure the height of every single person in an entire country. Of course when using a sample, it's desirable to try to get as close as possible to the mean of the population the sample represents. > From <https://dev.to/nestedsoftware/calculating-a-moving-average-on-streaming-data-5a7k>