1. S TATISTICS

2. W ARM - UP Mrs. Polasky has 4 classes. The data set blow shows the number of students in each of her classes. On average how many students does she have in her class. 20, 13, 15, 12

3. D ATA S ETS Data Set- is a collection of data. elements- are the members of a data set. Example: The data set is below 1, 3, 5, 7 The elements of the data set are 1 and 3, and 5 and 7.

4. Statistics- Are numerical values used to summarize and compare sets of data. Ex: The number of boys vs. girls in this class. What is the probability we will choose a boy to solve this problem?

5. D EFINITIONS YOU NEED TO KNOW Measure of central tendency- is a number used to represent the center or middle of a set of data values. Mean/(Average)- of n numbers is the sum of the numbers divided by n. It is Denoted as x, “x-bar”.

6. F IND THE M EAN Below is the number of cars sold each month by Dealer A and Dealer B. Find the mean of each set of data. Dealer A: 8, 9, 15, 25, 28, 16, 24, 18, 21, 14, 16, 10 Dealer B: 7, 4, 10, 18, 21, 30, 27, 20, 16, 18, 12, 9. Answer: Dealer A: 204 ÷ 12 = 17 On average dealer A sold 17 cars a month. Dealer B: 192 ÷ 12 = 16 On average dealer B sold 16 cars a month.

7. A NOTHER M EASURE OF C ENTRAL T ENDENCY Median- Of n numbers is the middle number when the numbers are written in order. Find the median of the following set of data. 6, 12, 14, 9, 7, 10, 15, 5, 12. Answer: 5, 6, 7, 9, 10, 12, 12, 14, 15. 10 is the median of the data.

8. Find the median of the data set. 76, 67, 34, 87, 76, 88, 75, 69, 72, 88 Answer: 34, 67, 69, 72, 75, 76, 76, 87, 88, 88 What do we do in this situation? Find the Median! 75 + 76 = 151 151 ÷2= 75.5 The median of the data set is 75.5.

9. Mode – of n numbers is the number or numbers that occur most frequently. Find the Mode of the following data set. 40, 37, 28, 44, 56, 34, 37, 49, 30, 29, 37, 28. Answer: 40, 37, 28, 44, 56, 34, 37, 49, 30, 29, 37, 28. The mode of this set of data is 37.

10. Find the mode of the following set of data. 87, 98, 77, 65, 77, 100, 80, 89, 90, 89, 91, 99, 77, 71, 69, 89, 100, 75, 84, 100. Answer: 87, 98, 77, 65, 77, 100, 80, 89, 90, 89, 91, 99, 77, 71, 69, 89, 100, 75, 84, 100. The mode of the data sets is 77, 89, and 100.

11. Measure of dispersion- is a statistic that tells you how dispersed, or spread out, the data values are. Range- The range is the difference between the greatest and least data values. What is the range of the data set? 10, 15, 20, 3, 9, 12, 19, 6, 7, 18, Answer: 20 – 3 = 17 The range of the data set is 17.

12. Find the Mean, Median, Mode, and Range of the data set. 100, 150, 100, 130, 125, 135, 140, 145, 100. Answer: Mean: 1125÷9=125 Median: 100, 100, 100, 125, 130, 135, 140, 145, 150. Mode: 100 Range: 150-100= 50 The Mean of the data set is 125, the median of the data set is 130, the mode is 100, and the range is 50.