CC34 MEASURES OF CENTRAL TENDENCY AND DISPERSION Objective

CC-34: MEASURES OF CENTRAL TENDENCY AND DISPERSION Objective: To find mean, median, mode, and range. By: Yolanda Torres, Daniel Cutino, Gabriella Castillo, George Guardia, Michael Montoya

Which player would you rather have on your team? Player 1 Player 2 Game Points Assists 1 12 8 23 5 2 10 4 3 15 4 12 2 4 11 5 25 3 5 12 3 5 2 ESSENTIAL UNDERSTANDING: YOU CAN USE DIFFERENT MEASURES TO INTERPRET AND COMPARE SETS OF DATA. How can you use the data to determine which player scores more points and which player makes more assists? You can find the total number of points scored and the total number of assists made for each player.

One way to summarize a set of data is to use a measure of central tendency. Mean, median and mode are all Measures of central tendency. You get the mean of the data when you add all the numbers, and then divide that value, by the number of numbers. You use the mean to find the average of a set of data. Mean = Average MEAN

The median is the number in the middle of a set of numbers. Ex: 45, 47, 48, 49, 51; the median of this set of numbers would be 48. MEDIAN

The mode is the value in a set of numbers that repeats the most. Ex: 3, 4, 5, 6, 6, 7, 7, 7, 8, 9; the mode would be 7 because it repeats the most. MODE

You get the range of a set of data, when you get the biggest number and subtract it by the smallest number. Ex: 15, 9, 7, 8, 14 First, you get 15 and 7 and then write it out. 15 -7=? The range is 8 RANGE

DO IT YOURSELF! Which class has a higher standard for being in the top half of the quiz scores? In order to be in the top half of the quiz scores, a student must have a greater quiz score than 50%. The median is the middle value, therefore 50% of the data are less than the median and 50% of the data are greater than the median. You need to calculate the median of each data set to determine which class has a higher standard for being in the top half of the quiz. Class A: Median: 3+4/2= 7/2=3. 5 Class B: Median: 5 QUIZ SCORES 7 6 6 3 6 5 5 4 6 4 4 3 3 2 2 1 1 1 0 Class A Class B 6

TRY SOME YOURSELF Find the mean, median, and mode of each data set. 1. Weights of books(oz): 12, 10, 9, 15, 16, 10 Mean: 12 2. Median: 11 Mode: 10 Golf scores: 98, 96, 98, 134, 99 Mean: 105 Median: 98 Mode: 98 3. Time spent on the Internet (min/day): 75, 38, 43, 120, 65, 48, 52 Mean: 63 Median: 52 Mode: No Mode

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