Measures of Central Tendency Mean, Median, Mode

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

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

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

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

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

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

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

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

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