Squared deviations

Squared deviations are a way to measure how different a number is from another number called the average, or mean. Imagine your friends took a test and the average of all their scores was 74. To measure how different each of your friends' scores was from the average, we can calculate "squared deviations". To calculate the squared deviation we take each of your friends' scores and subtract 74 (the average) from it. Then we take the answer and multiply it by itself. The bigger the answer we get from multiplying, the farther away from the average the score was.