Lesson 2-4 Pages Mean, Median, and Mode Lesson Check 2-3

What you will learn! How to find the mean, median, and mode of a set of data.

Measures of central tendency Mean Mode Median

What you really need to know! The mean is the sum of the data divided by the number of data items. The median is the middle number of the ordered data, or the mean of the middle two numbers.

What you really need to know! The mode is the number (or numbers) that occur most often. The mean, median, and mode are each measures of central tendency.

Find the mean, median, and mode for each set of data! 1, 5, 9, 1, 2, 6, 8, 2 Mean = 4.25 Median = 3.5 Mode = 1 and 2

Find the mean, median, and mode for each set of data! 82, 79, 93, 91, 95, 95, 81 Mean = 88 Median = 91 Mode = 95

The line plot shows the number of children of U. S. presidents. Would the mean, median, or mode best represent the number of children? Example 2:

x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x There are 46 numbers. Add them together and divide the sum by

x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x 143 ÷ 46  3.1 (mean)

x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x Since there are 46 numbers, the middle would be the 23 rd number from the each end of the list. That would be a 2 and a 3. Take the mean of these two numbers to get the median.

x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x 5 ÷ 2 = 2.5 (median)

x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x Median of 2.5 best represents the data! Mean = 3.1 Median = 2.5 Mode =

Extra: When the numbers are all in the same neighborhood, the MEAN is the way to go! If there is one number out of the neighborhood, then the MEDIAN is the choice!

Page 71 Guided Practice #’s 4-9

Pages with someone at home and study examples! Read:

Homework: Page 72 #’s #’s Lesson Check 2-4

Page 568 Lesson 2-4

Lesson Check 2-4

Mid-Chapter Practice Test Page 74 #’s 1-15

1. The number of pieces of data that fall within given intervals. 2. Example: Predicting profit earned by a company for the next year. 3. The greatest and least values, clusters of data, gaps in data, how the data is spread out, the range, and the mode (the most often number). 4. Sum of data divided by the number of terms in the data set.

Example 1: The table below shows the number of species of animals found at 30 major zoos across the U.S. Find the mean. Number of Species in Major U.S. Zoos

There are 30 numbers. Add them together and divide the sum by , ÷ 30 Calculator

Example 2: The table below shows the number of gold medals won by each country participating in the 2002 Winter Olympic games. Find the mean, median, and mode of the data Winter Olympics: Gold Medals Won

There are 25 numbers. Add them together and divide the sum by = 3.16÷ 25

Example 2: The table below shows the number of gold medals won by each country participating in the 2002 Winter Olympic games. Find the mean, median, and mode of the data Winter Olympics: Gold Medals Won

Order the numbers from greatest to least. Find the number or numbers in the middle of the list Winter Olympics: Gold Medals Won The median for this data is 2.

2002 Winter Olympics: Gold Medals Won The mode is the number or numbers that occur most often. The mode for this data is Winter Olympics: Gold Medals Won