Understanding Averages: What Happens When a New Score is Added?

To understand averages, let's look at a set of test scores.To find the average, we first add all the scores together.Adding eighty, ninety, eighty-five, and ninety-five gives us a total of three hundred and fifty.To find the average, we divide the total by the number of scores, which is four.Three hundred and fifty divided by four equals eighty-seven point five.On a number line, we can see how eighty-seven point five represents the central or typical score among all test results.This average gives us a single number that represents the typical performance across all four test scores.Now that we understand how to calculate an average, let's see what happens when we add a new score.Now that we understand how to calculate averages, let's learn how to predict whether an average will increase or decrease before doing any calculations.Here's our number line showing our current average of eighty-seven point five from our previous scores.Let's look at our first example. What happens when we add a score of seventy?Since seventy is below our current average of eighty-seven point five, we know the average will decrease. The new average becomes eighty-four.Now let's look at what happens when we add a score of one hundred instead.Since one hundred is above our current average, the average increases to ninety.Here's a practical tip: you don't need to calculate the exact average to know which direction it will move. Simply compare the new score to your current average.