Running average

Imagine you have some friends who all have different heights. Some are taller than others, and some are shorter. One way you can figure out how tall your group of friends is on average is by adding up everyone's heights and then dividing by the total number of friends. This gives you the mean or normal average height.

Now let's say that instead of just calculating the average height once, you want to update the average height every time one of your friends joins or leaves the group. Instead of starting over each time, you can use a running average.

A running average is like keeping a moving average of a set of numbers. In our example, you would start by calculating the mean height of the group of friends, just like before. As more friends join or leave, you update the average by adding the height of the new person or removing the height of the person who left, and dividing by the new total number of friends.

So, a running average is a way to calculate how things change over time by constantly updating the average as new data comes in. It's like a rolling average that keeps you up-to-date on the current value of something, instead of just giving you the average of a fixed set of data.