To understand how to approach a question about stem and leaf diagrams. Objectives To understand how to approach a question about stem and leaf diagrams. Edexcel GCSE Maths Spec B – Modular: Booster C © Pearson Education 2010. This document may have been altered from the original.

The number of people who completed the task The range of times Question The number of minutes taken to complete a sorting task are recorded in the following stem and leaf diagram. 3|6 means 36 3 1 2 2 2 3 4 5 7 4 3 4 5 5 6 7 8 5 1 2 3 4 5 6 6 6 6 6 6 7 9 6 1 1 1 2 3 4 7 9 7 3 5 Find: The number of people who completed the task The range of times The median time The mode Key 3|6 means 36 Edexcel GCSE Maths Spec B – Modular: Booster C © Pearson Education 2010. This document may have been altered from the original.

The number of people who completed the task Question The number of minutes taken to complete a sorting task are recorded in the following stem and leaf diagram. The number of people who completed the task 3|6 means 36 3 1 2 2 2 3 4 5 7 (8) 4 3 4 5 5 6 7 8 (7) 5 1 2 3 5 6 6 6 6 6 6 7 9 (12) 6 1 1 1 2 3 4 7 9 (8) 7 3 5 (2) = the number of values in the diagram. = 8+7+12+8+2 = 37 Key 3|6 means 36 Frequencies Edexcel GCSE Maths Spec B – Modular: Booster C © Pearson Education 2010. This document may have been altered from the original.

Question The number of minutes taken to complete a sorting task are recorded in the following stem and leaf diagram. 3|6 means 36 3 1 2 2 2 3 4 5 7 4 3 4 5 5 6 7 8 5 1 2 3 4 5 6 6 6 6 6 6 7 9 6 1 1 1 2 3 4 7 9 7 3 5 b. The range of times = largest - smallest = 75 – 31 = 44 seconds Key 3|6 means 36 Edexcel GCSE Maths Spec B – Modular: Booster C © Pearson Education 2010. This document may have been altered from the original.

There are 37 values, so the middle will be: Question The number of minutes taken to complete a sorting task are recorded in the following stem and leaf diagram. 3|6 means 36 3 1 2 2 2 3 4 5 7 4 3 4 5 5 6 7 8 5 1 2 3 4 5 6 6 6 6 6 6 7 9 6 1 1 1 2 3 4 7 9 7 3 5 c. The median time = the middle value. There are 37 values, so the middle will be: Key 3|6 means 36 Median = 54 seconds Edexcel GCSE Maths Spec B – Modular: Booster C © Pearson Education 2010. This document may have been altered from the original.

= the value that comes up most often. Question The number of minutes taken to complete a sorting task are recorded in the following stem and leaf diagram. 3|6 means 36 3 1 2 2 2 3 4 5 7 4 3 4 5 5 6 7 8 5 1 2 3 4 5 6 6 6 6 6 6 7 9 6 1 1 1 2 3 4 7 9 7 3 5 d. The mode = the value that comes up most often. This is the largest run of the same number. Key 3|6 means 36 Mode = 56 seconds Edexcel GCSE Maths Spec B – Modular: Booster C © Pearson Education 2010. This document may have been altered from the original.

Remember that you must subtract when finding the range. Summary Remember that you must subtract when finding the range. When reading values from the diagram it’s very important to remember that you have to put the ‘leaves’ and ‘stems’ together to get 2-digit numbers. Edexcel GCSE Maths Spec B – Modular: Booster C © Pearson Education 2010. This document may have been altered from the original.