Do Now 1/30/12 Copy HW in your planner. Copy HW in your planner. Text p. 278, #1-13 all, #20 & 21 Text p. 278, #1-13 all, #20 & 21 In your notebook, put the following heading on the top of the page. In your notebook, put the following heading on the top of the page. Section 7.1 “Mean, Median, Mode, and Range” Section 7.1 “Mean, Median, Mode, and Range”

Chapter 7 “Collecting, Displaying, and Analyzing Data” Section 7.1 “Mean, Median, Mode, and Range” Section 7.2 “ Box-and-Whisker Plots ” Section 7.3 “Populations and Samples

Objective SWBAT find the mean, median, and mode of a set of numbers and data. SWBAT find the mean, median, and mode of a set of numbers and data.

Section 7.1, “Mean, Median, Mode, and Range the measures used to represent the “middle” of a data set. There are 3 types: (1) Mean (2) Median (3) Mode Central Tendency Range the difference between the greatest and least values

FINDING A MEAN To find the MEAN of a set of numbers, add the numbers and divide the sum by how many numbers are in the set. MEAN is another word for AVERAGE.

Computing Means Sally Joe from Idaho, is a big-time bowler. She bowled three games with the following scores: Sally Joe from Idaho, is a big-time bowler. She bowled three games with the following scores: 197, 188, 182 What is her mean score? What is her mean score? = = This is Sally Jo’s AVERAGE or MEAN

Try It Out!! Find the mean of the data 1) 6, 10, 12, 8, 14 2) 97, 88, 82 3) 45, 16, 72, 54 1) = 50 = ) = 267 = ) = 187 =

FINDING A MEDIAN To find the MEDIAN of a set of numbers, first write the numbers in order. The median is the middle number or the mean of the two middle numbers. Even amount of # in set Odd amount of # in set Even amount of # in set Odd amount of # in set MEDIAN the middle number in a set of data. the middle number in a set of data.

Finding the Median Find the median age of Sally Sue’s family of 7. 41, 32, 36, 17, 41, 51, 32 Put the list IN ORDER than locate the M MM MIDDLE #. 17, 32, 32, , 41, 41, 51 Find the median age of Sally Moe’s family of 6. 41, 32, 36, 22, 51, 32 Put the list IN ORDER than find the M MM MEAN of the MIDDLE 2 #s. 22, 32, , , 41, = 68/2 = 34

FINDING A MODE To find the MODE of a set of numbers, first write the numbers in order. The mode is the number that appears most often. MODE the most often number in a set of data. the most often number in a set of data.

Finding the Mode Find the mode of the following test scores in the class. 80, 88, 89, 90, 92, 90, 87, 90, 100, 84, 90 Put the list IN ORDER, the mode is the number that appears the M MM MOST often. 80, 84, 87, 88, 89, , 90, 90, 90, 92, 100

Outlier an extreme value in a set of data that is much greater or less than the other values in the set

Describing Data Best the data are spread fairly evenly the data set has an outlier the data involve a subject in which many data points of one value are important, such as election results meanmedianmode Most Useful When Measure

Interpreting Data The line plot shows the number of miles 21 members of the cross-country team ran in a week. Find the mean, median, and mode from the line plot below. Which measure of central tendency best describes the data? 4567 x x x x x x x x x x x x x x x 3 x x x x x x Mean = 6.14 Median = 6 Mode = 8 The mean best describes the data because it is spread fairly even. 10 runners ran more than 6 miles and 10 runners ran less than 10 miles.

Exploring the Effects of Outliers on Measures of Central Tendency The data shows Sara’s scores for the last 5 math tests: 88, 90, 55, 94, and 89. Identify the outlier in the data set. Then determine how the outlier affects the mean, median, and mode of the data. Then tell which measure of central tendency best describes the data with the outlier. outlier55 55, 88, 89, 90, 94

With the Outlier… outlier 55 55, 88, 89, 90, = ÷ 5 = 83.2 The mean is , 88, 89, 90, 94 The median is 89.There is no mode. mean:median:mode: Without the Outlier… 55, 88, 89, 90, = ÷ 4 = The mean is , 89, 90, 94 The median is 89.5.There is no mode. mean:median:mode: + 2 = 89.5

Homework Text p. 278, #1-13 all, #20 & 21 Text p. 278, #1-13 all, #20 & 21

Find the median and mode for the following sets of data. 1) 1, 1, 2, 2, 2, 4, 4, 4, 4, 6, 7, 8, 9 2) 2, 7, 4, 9, 2, 5, 6, 11, 9, 4, 8, 10 3) 14, 22, 33, 21, 87, 90, 43, 54, 55, 11, 22, 12 4) 10, 100, 1000, 99, 999, 3, 33, 333, 10, 3, 9 1)Median = 4 Mode = 4 2) Median = 6.5 Mode = 2,4,9 3) Median= 27.5 Mode = 22 4) Median = 33 Mode = 3,10 2, 2, 4, 4, 5, 6, 7, 8, 9, 9, 10, 11 11, 12, 14, 21, 22, 22, 33, 43, 54, 55, 87, 90 3, 3, 9, 10, 10, 33, 99, 100, 333, 999, 1000