15/01/2019 Starter L.O. To be able to Draw a stem and leaf diagram from a list of data Use a stem and leaf diagram to interpret data Key Words stem, leaf, key, discrete, averages, data Starter

CONTENTS – Click to go to… 15/01/2019 CONTENTS – Click to go to… DRAWING STEM AND LEAF USING STEM AND LEAF

15/01/2019 DRAWING A STEM AND LEAF

15/01/2019 A stem and leaf diagram show ordered discrete data. Each number is broken up into two parts. For example, you might split the number 23 into a stem of 2 and a leaf of 3 Your key would look like this... Key: 2 3 = 23 So the stem tells us how many tens and the leaf tells us the units of each data value

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15/01/2019 Stem and leaf Data must be in order Think about how you will split each number into a stem and a leaf Put them into the diagram Cross out each number as you add it Space them out evenly Don’t forget your KEY!

15/01/2019 Example 7, 16, 37, 45, 22, 37, 11, 4, 35, 29, 33 Key: 2 2 = 22 1 2 3 4 Tens 4 7 Units 1 6 2 9 3 5 7 7 5

15/01/2019 Task – on your mini whiteboards, draw a stem and leaf diagram for the following data 12, 25, 42, 7, 15, 15, 24, 19, 5, 46, 36, 38, 27, 3, 26, 45, 33, 27, 24

1/15/2019 Stem-and-leaf diagrams are useful as they contain the same degree of accuracy as the original data.

15/01/2019 Task – Put each set of data into a stem and leaf diagram 44, 39, 22, 29, 37, 21, 41, 30, 30, 27, 42 54, 54, 59, 61, 42, 50, 63, 47, 47, 60, 59, 56, 57 2 3 4 1, 2, 7, 9 0, 0, 7, 9 1, 2, 4 4 5 6 2, 7, 7 0, 4, 4, 6, 7, 9, 9 0, 1, 3 73, 72, 90, 92, 78, 102, 99, 73, 90, 100 9, 12, 3, 28, 3, 3, 3, 0, 11, 10, 5, 9, 29, 31, 1, 6 7 8 9 2, 3, 3, 8 0, 0, 2, 9 10 0, 2 1 2 0, 1, 3, 3, 3, 3, 5, 6, 9, 9 0, 1, 2, 8, 9 3

15/01/2019 Discussion – For the number below, can you think of how they could be represented on a stem and leaf? What would the key look like? Show me ideas on your mini whiteboards… 145 1.7

15/01/2019 Task – draw a stem and leaf diagram to show one of these sets of data. Choose your level of challenge… Easy Medium Hard

15/01/2019 Stem-and-leaf diagrams can be used to compare two sets of data. The back-to-back stem-and-leaf diagram shown below compares the height of 15 boys and 14 girls from a form group. A stem-and-leaf diagram comparing the heights of pupils in a form group The diagram shows that the boys in the form group are typically taller than the girls. The heights of the boys are also more varied than the girls’ heights.

15/01/2019 USING A STEM AND LEAF

15/01/2019 We also need to be able to use a stem and leaf diagram to analyse the data that it represents. What information do you think we might be able to find out from a stem and leaf diagram? 2 1 9 2 6 3 4 5 7 7 7 4 2 6 9 5 0 4 Key: 2 1 = 2.1

a) Calculate the median. b) Calculate the range. 15/01/2019 Example 4 5 6 7 8 1 1 3 3 4 5 5 8 8 9 2 3 4 7 7 8 9 9 0 0 4 5 6 0 1 1 0 4 7 9 5|2 = 52 a) Calculate the median. b) Calculate the range. = 63

a) Calculate the median. b) Calculate the range. 15/01/2019 Example 4 5 6 7 8 1 1 3 3 4 5 5 8 8 9 2 3 4 7 7 8 9 9 0 0 4 5 6 0 1 1 0 4 7 9 5|2 = 52 a) Calculate the median. b) Calculate the range. = 63 = 81 - 40 = 41

15/01/2019 2 1 2 6 9 3 4 5 7 7 7 4 2 6 9 9 5 0 4 Key: 2 1 = 2.1 This stem and leaf diagram shows the heights, to the nearest metre, of a number of trees: ALL: How many trees were there in the sample? MOST: What is the range of heights of the trees? What is the modal height of tree? SOME: What is the median tree height?

15/01/2019 Task 1 2 3 4 8 8 9 1 1 1 4 4 8 9 0 3 5 5 7 8 8 9 2 2 3 3 5 6 8 8 1 1 3 3 5 8 This stem and leaf diagram shows data about the areas of some photographs in an old album. Key 4 1 represents 41cm a) Write down the number of photographs that have an area of 38cm2 b) What is the total number of photographs? c) Work out the range of the areas of the photographs d) What is the modal area of the photographs?

CLICK FOR SOLUTIONS… 15/01/2019 Task - How confident do you feel drawing and using stem and leaf diagrams? Choose SUPPORT, CORE or EXTENSION from the available worksheets… CLICK FOR SOLUTIONS… 0 5 7 8 8 1 0 0 0 0 2 5 5 5 5 6 2 0 0 0 4 5 3 3 5 15 35 – 5 = 30 13 times 2 3 7 8 3 1 4 5 6 4 1 2 4 5 5 5 0 2 3 41 53 – 23 = 30 12 teachers KEY KEY 0 1 2 4 6 6 1 1 3 3 5 5 5 8 9 9 2 2 2 4 5 5 8 8 9 3 0 5 4 6 19 46 – 1 = 45 2 sentences 1 8 8 9 2 1 1 2 2 4 4 8 9 3 0 1 2 3 24 33 – 18 = 15 6/15 or 2/5 KEY KEY

15/01/2019 Calculate the median, mode and range for each stem-and-leaf diagram.

15/01/2019 Exam question

15/01/2019 Spot the errors! 0 2 5 7 1 1 9 2 6 2 4 5 8 8 8 3 2 6 4 9 The range of the data is 40 The median of the data is 25 The mode of the data is 8