Stem and Leaf Diagrams Stem and leaf diagrams
- Slides: 6
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 n = 20 Class Maths Marks 1 0 2 2 6 8 2 3 4 9 5 9 3 0 0 2 6 8 9 9 4 0 4 5 2 / 3 means a mark of 23
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) 5 86689889 We need the stems We need the Leaves 6 6091227213260739 7 422224 We need to reorder the leaves We need to write in n We need the key n = 15 6 / 2 means 62 beats per minute
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 Pocket money Note this gives us the same diagram as the previous example. This shows the importance of the title and key. 5 6 8 8 9 6 0 1 2 2 3 6 7 9 7 2 2 4 n = 15 6 / 2 means £ 6. 20
Draw Stem and Leaf Diagrams for the following sets of data Speed in mph The speed of cars, in mph, passing police speed check 3 2 4 5 6 7 8 9 35 46 32 48 53 58 60 39 36 48 34 51 42 37 53 42 51 38 1 1 3 3 8 4 2 2 6 8 8 6 0 n = 18 4/3 means 43 mph Distance in metres John took a note of how far, in metres, he was able to hit a golf ball 10 1 5 8 108 115 132 121 101 122 138 127 105 112 118 127 129 120 139 136 131 121 111 129 137 12 0 1 1 2 7 7 9 9 11 1 2 5 8 13 1 2 6 7 8 9 n = 21 12/3 means 123 m
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. Maths marks for class 1 A 8 0 Maths marks for class 1 B 6 8 9 8 5 3 1 1 2 2 2 5 5 8 9 4 4 5 2 0 0 1 1 6 7 6 4 3 1 1 0 3 3 7 7 7 3 3 4 1 n = 19 3/2 means a mark of 32 n = 20 How many students in 1 A had a mark of 31? 2 How many students in 1 B had a mark of 12? 3 1 A Which class appears to be best at Maths?
Use the Back to Back Stem and Leaf Diagram to answer the questions Books borrowed from the library This week Last 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 = 10 2/0 represents 20 books How many books were borrowed at level 3 this week 65 ? How many books were borrowed at level 4 last week ? 129 Which week was best for the library How many books were borrowed last week altogether This ? week ? 387