Mean, Median, Mode, & Range Lesson 3-1 Pg. # 88-90

CA Content Standards  Statistics, Data Analysis, and Probability 1.1: I can compute the range, mean, median, and mode of data sets.  Statistics, Data Analysis, and Probability 1.4: I know why a specific measure of central tendency (mean, median, mode) provides the most useful information in a given situation.  Math Reasoning 1.0: I make decisions about how to approach problems.

Vocabulary: MEASURES OF CENTRAL TENDENCY  Measuring tools (such as mean, median, and mode) that show what is typical or common in a set of data.

Vocabulary: MEAN  The sum (+) of all the items in a data set divided by the number of items.  AKA the Average

Vocabulary: MEDIAN  The middle number when data are arranged in order from least to greatest.  AKA the Middle Number

Vocabulary: MODE  The number or numbers that occur most often in a set of data.  AKA the Most Popular Number

Vocabulary: RANGE  The difference (-) between the greatest and least numbers in a set of data.

Objective  Compute the mean, median, mode, and range of sets of data.  Math Link: You know how to order, add, subtract, and divide whole numbers and decimals. Now you will learn how to use these skills to find the mean, median, mode, and range of a set of data.

Example 1.  This table shows the number of hours of math homework 7 of my students do per night.  Find the mean, median, mode, and range of this data. Number of Hours of Homework: 7 Students StudentABCDEFG No. of Hours

To find the mean:  Add all the values together: = 21  And divide by the number of students (values you added together): 21/ 7 = 3  This calculation shows us that Miss Flores’ students spend an average of 3 hours doing math homework each night.

To find the median:  Arrange the values in the table from least to greatest:  And find the middle number (if the set has an odd number of values)… 3  This calculation shows us that Miss Flores’ students spend an average of 3 hours doing math homework each night.

To find the mode:  Look for the number that repeats most often:  Sometimes there is no mode or there may be more than one mode. In this case, both 2 and 4 repeat twice, so they are our modes.

To find the range:  The range can tell you if the data are spread far apart or clustered. To find the range, identify the smallest and largest value  Subtract the least number from the greatest number = 4  A small range shows us that all the values are pretty close together. This must mean that most students spend about the same amount of time doing homework every night.

The Moral of the Story:  Mean, median, and mode are all statistical measures of the typical value or central tendency of a group. The range describes how closely the data are clustered together.

Whateverville’s Temp.- One Week DayTemperature (°C) Sunday50 Monday62 Tuesday90 Wednesday106 Thursday10 Friday50 Saturday0

Whateverville’s Temp.- Ten More Days DayTemperature (°C) Sunday48 Monday45 Tuesday63 Wednesday51 Thursday101 Friday69 Saturday55 Sunday62 Monday53 Tuesday57