# Drawing Stem and Leaf Diagrams Teach GCSE Maths Petrol Consumption (mpg) 8 7 6 58 0 87 Key: 5 7 means 57 mpg 3 99 116.

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Drawing Stem and Leaf Diagrams Teach GCSE Maths Petrol Consumption (mpg) 8 7 6 58 0 87 Key: 5 7 means 57 mpg 3 99 116

"Certain images and/or photos on this presentation are the copyrighted property of JupiterImages and are being used with permission under license. These images and/or photos may not be copied or downloaded without permission from JupiterImages" © Christine Crisp Drawing Stem and Leaf Diagrams Data from the Office for National Statistics which is included in this presentation is reproduced under the terms of the click-use licence.

58 59 6061 6683 57 e.g.1The table gives the 10 “best” petrol consumption figures (mpg) for cars in 2006. Draw a stem and leaf diagram to display the data. 1.Decide on the size of numbers in the stem: A spread from 57 to 83 suggests a stem in tens, from 5 tens to 8 tens. Petrol Consumption (mpg) 8 7 6 58 0 87 Key: 5 7 means 57 mpg 3 2.Check the numbers are in order before writing the leaves. Start with the smallest. 99 116 3.Give a title and key. Crown Copyright 1997 - 2006 Source: Vehicle Certification Agency (VCA)

e.g.2.The table gives the body mass index (BMI) of 18 army recruits. (a) Draw a stem and leaf diagram to show the data. (b) Find the median. 25·425·726·026·826·927·1 27·6 27·728·128·228·7 28·828·929·329·629·831·1 BMI is given by weight (kg) / (height (m)) 2 e.g. weight = 74 kg, height = 1·69 m BMI = 74 ÷ (1·69) 2 = 25·9 In 2006, the maximum for army recruits was increased from 28 to 32. Tell your partner what numbers you would choose for the stem. Ans: The best choice is 25, 26,... 31 The leaves will show the tenths.

25·425·726·026·826·927·1 27·6 27·728·128·228·7 28·828·929·329·629·831·1 Solution: Key: 25 4 means 25·4 Body Mass Index of 18 army recruits 1 863 98721 980 74 31 30 29 28 27 26 25 1667 (a) e.g.2.The table gives the body mass index (BMI) of 18 army recruits. (a) Draw a stem and leaf diagram to show the data. (b) Find the median.

Key: 25 4 means 25·4 Body Mass Index of 18 army recruits 1 863 9872 980 74 31 30 29 28 27 26 25 166 1 7 Solution: The total frequency is even so we need the mean of the 2 middle values: (b) Find the median. Median is ½ (27·7 + 28·1) = 27·9 Tell your partner which values we need. We need the mean of the 9 th and 10 th... 27·7 and 28·1

SUMMARY 1.Decide on the size of numbers in the stem. 2.Check the numbers are in order before writing the leaves. Start with the smallest and work away from the stem. 3.Give a title and key.

Exercise 1. Stem and leaf diagrams are to be drawn for the following data set which gives the ages of 27 people in a restaurant. 4245515357 5960 61 6263 65 66 67 6870 71 73 (a) Write down sensible numbers to use in the stem. (b) State the size of the numbers in the leaves. Answer: For example, (a) 4, 5, 6, 7 (b) Units (c) Draw the diagram. If you had a different answer to (a), use your numbers and decide if they work well.

Exercise 4245515357 5960 61 6263 65 66 67 6870 71 73 Key: 4 2 represents 42 52 7 6 5 4 731977 0111233556778 110003 Ages of 27 people in a Restaurant (c) Answer

Exercise 2. Stem and leaf diagrams are to be drawn for the following data set which gives the temperatures of 18 towns (  C ) on 21 st February 2007. 7·27·27·57·57·77·78·38·38·78·78·78·78·78·78·98·99·09·0 9·39·39·79·710·110·610·9 11·111·411·6 (a) Write down sensible numbers to use in the stem. (b) State the size of the numbers in the leaves. Answer: (a) For example, 7, 8, 9, 10, 11 (b) Tenths Now draw the diagram. If you had a different answer to (a), use your numbers and decide if they work well. Adapted from Crown copyright data supplied by the Met Office.

Exercise 7·27·27·57·57·77·78·38·38·48·48·48·48·58·58·88·89·09·0 9·39·39·79·710·110·610·9 11·111·411·6 037 44385 February temperatures ( 18 towns ) (c) 10 9 8 7 11 527 146 Answer Key: 7 2 represents 7·2  C 9961

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