Mean, Median, Mode and Range Lesson 2-6 and 2-7

Mean The mean of a set of data is the average. Add up all of the data. Divide the sum by the number of data items you have.

Example: Find the mean. 4, 16, 20, 40 First, add = 80 There are 4 items. Divide the sum (80) by 4. The mean is 20.

Outliers Outliers are values and are MUCH higher or lower than the other numbers in the data set –If the outlier is bigger it makes the mean higher than most of the data set. –If the outlier is smaller it makes the mean smaller than the numbers in the data set. * Without outliers, the mean is better represented*

Median The median is the data point that is in the middle when the data is listed in order from LEAST TO GREATEST If there are two numbers in the middle (an even number of items), then find the mean of the two middle numbers.

Examples: Find the median. 13, 16, 17, 19, is the median. 3, 5, 6, 9 Here, the 5 and 6 are both in the middle = divided by 2 = 5.5. The median is , 17, 25, 13, 16

Example: Find the mode. 5, 4, 6, 11, 5, 7, 10, 5 The mode is 5. 11, 24, 2, 69, 11, 9, 9 The mode is 11 and 9.

Mode The mode is the data item that appears the most. (there can be more than 1 mode) If all data items appear only once, then there is no mode.

Range The range of a set of data is the difference between the greatest and the least values. Ex) 65, 68, 72, 65, 80, 55, 65 Range: 80 – 55 = 25

Find the Median, Mode and Range or the data. Number of Calories in Selected Vegetables (per serving) Median: 28 Mode: 15 and 25 Range: 80