Application of Number

Level 2

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Range - Tutorial 4

The range is the difference between the largest and the smallest number.

The range is useful for findng how variable something can be.

For example two fish and chip shops could give you the same average number of chips in a bag, but one shop could have a range of 20 and the other shop could have a range of 5. This means that the first shop changes the amount of chips by a lot. The second chip shop always gives you about the same number of chips because it has a smaller range.

To find the range:

E.g. 1

If we wanted to find the range of this set of numbers.

The data:

10, 12, 12, 10, 9, 11, 11, 13, 11, 9, 8

1. First find the largest and smallest numbers.

13 and 8

2. Take the smallest from the largest

13 - 8 = 5

In this case the range was 5.

E.g. 2

If we wanted to find the range exam score of two different classes of students.

The data:

Class A - 90, 89, 90, 85, 90, 86, 89, 90, 85, 90, 84, 83

Class B - 86, 87, 99, 89, 91, 80, 87, 93, 82, 85, 79, 75

1. First find the largest and smallest numbers for each class.

Class A ->   90 and 83

Class B ->   99 and 75

2. Take the smallest from the largest.

Class A ->   90 - 83 = 7

Class B ->  99 - 75 = 24

The range for Class A was 7.
The range for Class B was 24.

This means that the results for Class A are close together and not very variable. So all of the students are performing close together. (Small range)
The results for Class B are very variable, so some students are performing very well and some are performing a lot worse than other members of the class. (Large range)

To find the range

To practise finding the mode try this assessment.

Then go on to the next tutorial.

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