1. Stem and Leaf Diagrams Stem and leaf diagrams are a pictorial way of showing statistics The important parts of a stem and leaf diagram are The Title The stem The leaves in order starting from the stem The number of items The key Class Maths Marks 12341234 0 2 2 6 8 3 4 9 5 9 0 0 2 6 8 9 9 0 4 5 n = 20 2 / 3 means a mark of 23

2. A group of students measured their pulse rates in beats per minute. The results were. 66 69 62 58 74 56 67 72 61 62 59 60 72 58 63 Draw a Stem and Leaf diagram to show this We need a title Pulse rates (beats per minute) We need the stems 567567 We need the Leaves 8 6 9 8 6 9 2 7 1 2 0 3 4 2 2 We need to reorder the leaves 6 8 8 9 0 1 2 2 3 6 7 9 2 2 4 We need to write in nn = 15 We need the key 6 / 2 means 62 beats per minute

3. A group of students were asked how much pocket money they get. The results were. £6.60 £6.90 £6.20 £5.80 £7.40 £5.60 £6.70 £7.20 £6.10 £6.20 £5.90 £6.00 £7.20 £5.80 £6.30 Draw a Stem and Leaf diagram to show this 6 8 8 9 0 1 2 2 3 6 7 9 2 2 4 n = 156 / 2 means £6.20 567567 Pocket money Note this gives us the same diagram as the previous example. This shows the importance of the title and key.

4. Draw Stem and Leaf Diagrams for the following sets of data The speed of cars, in mph, passing police speed check 35 46 32 48 53 58 60 39 36 48 34 51 42 37 53 42 51 38 John took a note of how far, in metres, he was able to hit a golf ball 108 115 132 121 101 122 138 127 105 112 118 127 129 120 139 136 131 121 111 129 137 Speed in mph 3 2 4 5 6 7 8 9 4 2 2 6 8 8 1 1 3 3 8 6 0 n = 18 4/3 means 43mph Distance in metres 10 1 5 8 11 1 2 5 8 12 0 1 1 2 7 7 9 9 13 1 2 6 7 8 9 n = 21 12/3 means 123m

5. Stem and Leaf diagrams can be used to compare 2 sets of data. To do this we draw a back to back stem and leaf diagram. 0123401234 8 8 5 3 9 4 4 5 2 0 6 4 3 1 1 0 7 3 3 6 8 9 1 2 2 2 5 5 8 0 0 1 1 6 7 3 7 7 1 Maths marks for class 1AMaths marks for class 1B n = 19n = 203/2 means a mark of 32 How many students in 1A had a mark of 31? How many students in 1B had a mark of 12? Which class appears to be best at Maths? 2 3 1A

6. Use the Back to Back Stem and Leaf Diagram to answer the questions Books borrowed from the library This weekLast week 2 0 1 4 1 3 1 5 6 7 4 4 3 4 0 4 5 1 0 5 2 4 1 6 3 n = 10n = 10 2/0 represents 20 books How many books were borrowed at level 3 this week ? How many books were borrowed at level 4 last week Which week was best for the library How many books were borrowed last week altogether 65 ? 129 ?This week ? 387