2. Unit 9 Lesson 5 Measures of Center-STEM AND LEAF PLOTS

3. Vocabulary Leaf – the last number Stem – anything to the left of the very last number (sometimes that is “0” ; sometimes it is two numbers) Key – an explanation of the stem and leaf

4. High temperatures for the last week: 72, 78, 87, 90, 88, 86, 87, 89 Stem 7 8 9 Leaf 2 8 6 7 7 8 9 0 7 2 = 72 degrees

5. Stem and Leaf Plot Here are the numbers of homeruns that Babe Ruth hit in each of his 15 years with the New York Yankees from 1920-1934: –54, 59, 35, 41, 46, 25, 47, 60, 54, 46, 49, 46, 41, 34, 22

6. 2 3 6 7 8 9 9 0 0 1 1 1 1 2 2 4 4 4 4 5 5 5 6 6 6 7 7 7 7 8 0 1 1 1 2 4 4 5 8 9 StemLeaf 456456 Age of United states Presidents at their First Inauguration: 57 61 57 57 58 57 61 54 68 51 49 64 50 48 65 52 56 46 54 49 50 47 55 54 42 51 56 55 51 54 51 60 62 43 55 56 61 52 69 64 (Through the 40 th presidency) Key: 5 7 means 57

7. Stem and Leaf Diagrams How to Draw One: 1. Put the first digits of each piece of data in numerical order down the left-hand side 2. Go through each piece of data in turn and put the remaining digits in the proper row 3. Re-draw the diagram putting the pieces of data in the right order 4. Add a key

8. Stem and Leaf Diagrams Remember: - Always put in a Key - Always put your data in Order Median: - to work out the median, you must find the middle value - if there are two middle values, you need the average Range: - to work out the Range, subtract the smallest number from the biggest

9. Stem and Leaf Diagrams The stem & leaf diagram below shows the masses in kg of some people in a lift. (a)How many people were weighed? (b)What is the range of the masses? (c)Find the median mass. Stem Leaf 3 4 5 6 7 8 1 4 3 36 0 3 4 8 1 2 2 7 1 6 2 tens units (a) 16 people. (b) 86 – 31 = 55 kg Median is the mean of the 8 th and 9 th data values. (c) 56 kg

10. Using Stem-and-Leaf Plots What was the least number of cookies sold? Boxes of Girl Scout Cookies Sold by Troop 220 40 boxes

11. Using Stem-and-Leaf Plots What was the largest number of cookies sold? Boxes of Girl Scout Cookies Sold by Troop 220 94 boxes

12. Using Stem-and-Leaf Plots Find the median of the data Find the middle leaf… 63 boxes Boxes of Girl Scout Cookies Sold by Troop 220

13. Using Stem-and-Leaf Plots Find the mode of the data Look for the number that occurs most often in a row of leaves 63 boxes Boxes of Girl Scout Cookies Sold by Troop 220

14. Practice Pages 323 and 323 #1-16