When you want to know what number of something is most usual, you look to a mean, median or mode to tell you the answer. The mean, the median and the mode are numbers representing central values. According to Purplemath, a website recognized for its math teaching role by PBS, the Wall Street Journal, and Education World, the mean is commonly referred to as the average, the median is the middle, and the mode is the most frequently occurring number. By noticing how each of these numbers is computed, you can understand the significance of each term.
Instructions
Calculate the Mean
1. List your numbers. List every instance of the number once. For example, when finding the average mean in a list of grades, you might have a list like the following: 56, 65, 70, 70, 82, 84, 89, 90, 90, 90 and 98.
2. Add up the numbers, including each instance of all the numbers. In the example, the total amount would be 884.
3. Count up the number of values you added up to make the total. Include each instance of each number as a separate item. In the example, the total number of values would be 11.
4. Divide the total amount of all the numbers by the total number of values used to make up that total. In the example above, the equation would be 884 divided by 11. The mean average, then, would be 80.36.
Calculate the Median
5. Arrange your data. An example of something you might want to figure a mathematical median of could be the number of hours worked in a week. Write down the number of hours worked by each person separately, even if some of them worked the same number of hours. . In the example, the numbers might be the following: 37, 40, 41, 46, 41, 40, 56, 50, 40, 41, 37, 35 and 42.
6. Rewrite this list in order from lowest to highest value, including every instance of each number. In this case, the list would now read: 35, 37, 37, 40, 40, 40, 41, 41, 41, 42, 46, 50 and 56.
7. Add up the number of values present in your list. In this example, there are 13.
8. Find the middle number, also called the median. Purplemath suggests you use the formula: "([the number of data points] +1) divided by 2." In this instance, there are 13 data points or values, so add one to get 14, and then divide by 2 to get 7. The seventh number, 41, is the median.
Calculate the Mode
9. List each number that is used, as many times as it is used. If you want to find the number of children per family that is most common among your friends, write down the number of children each has. The numbers might be 1, 1, 2, 2, 2, 2, 3, 6, 5, 5, 7, 2, 2, 4 and 3.
10. Sort the list by numbers. Put all the ones together, all the twos together, and so on. In the example, you would have 2 ones, 6 twos, 2 threes, 1 four, 2 fives, 1 six, and 1 seven.
11. Choose the number that occurs most often. In the example given, there are more twos than any other number, so 2 is the mode. If there is not just one number that is repeated more often than the others, then the group of numbers has no mode.
Tags: number values, each number, number hours, number that, data points, down number, each instance