# Tutorial Two: Averages… the easy way The average height of an American male is 5’10”. The average height of an American female is 5’5”. The average price of a home sold in the United States in 2010 was \$272,900. We use averages all the time.  In fact, the average is one of the most widely used tools in mathematics. It is so important, that mathematics defines several different types of averages: arithmetic mean, geometric mean, harmonic mean, mode, and median.

When most people think of the word average, they generally think of an arithmetic mean. The arithmetic mean, or average, of two numbers is found quite easily. Imagine you are given two numbers, 7 and 3, and are asked to find their average. Most people will quickly arrive at 5 as the answer by adding the two original numbers together and dividing that result by two. This approach is called the addition mean equation and is mathematically written as:

Avg = (A+B)/2

In fact, if you ask 10 people to find an average, it is quite likely that each will use this approach; adding the values and dividing that sum by two to arrive at 5 as the average of 7 and 3. This equation for the average of two numbers is also called the mid–point equation.

FACT: Because the arithmetic mean was used long before Einstein was born, you don’t need relativity theory to explain or calculate an average.

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