1. Measures of Central Tendency
Mean, Median, Mode

2. Vocabulary Measures of center – types of averages for a data set Mean
Median
Mode

3. Which Measure of Center is Best?
Mean – when the data set has no very high or low numbers
Median – when the data set has some high or low numbers and most of the data in the middle are close in value
Mode – when the data set has many identical numbers

4. Things to Know
Which measure of central tendency is always found in the data set itself?
Median
Mean
Mode
All of the above

5. Example 1
CLIMATE The average annual number of days of precipitation for selected cities in the Southwest is shown in the table below. Which measure of central tendency best describes the data?
Average Annual Precipitation (days) in Selected
Southwestern U.S. Cities 59 32 72 26 36 52 90 43 63

6. Weight (in pounds) of Sixth-Grade Boys
Your Turn
WEIGHT The weights (in pounds) of nine sixth-grade boys are shown below. Which measure of central tendency best describes the data?
Weight (in pounds) of Sixth-Grade Boys 78 68 83 75 79 90
122 76 81

7. Example 2 Your Turn Which measure best describes the data:23 22 15 36 44
Find the mean, median, and mode(s) of the data. Choose the measure that best represents the data.
126 62
144 81
103

8. Example 3 Your Turn Which measure best describe the cost of the CDs?
$12
$14
$18
$10
Find the mean, median, and mode(s) of the data. Choose the measure that best represents the data. 12 13 40 95 88 7

9. Example 4
Your Turn
Find the mean, median, and mode(s) of the data. Choose the measure that best represents the data. 2 8 10 12 56 9 5 4
Find the mean, median, and mode(s) of the data. Choose the measure that best represents the data. 48 12 11 45 43 32

10. Example 5
Your Turn
Which measure of center would be used to show what pet most students had?
Which situation would require finding the median as an appropriate center of measure?
The temperatures recorded were either 20 degrees or 25 degrees
All of the temperatures recorded were all between 80 degrees and 90 degrees
A few of the temperatures recorded were very low or very high
All of the temperatures recorded were 55 degrees