# Unit 18 Section 3 : Measures of Central Tendency

Dispersion is how spread out a set of data are. One measure of dispersion is the range.
The range is the difference between the highest and lowest values in the data set.

 Range = Highest Value - Lowest Value

Example
Look at this data: The highest value is 22 and the lowest value is 3, so the range is 22 - 3.
The range of this data is 19

Example Questions
Work out the answer to the questions below then click to see whether you are correct. (a) What is the range of the data illustrated in the vertical line diagram on the right? (b) Look at the values below.
-5, -3, 2, 4, 6, 7, 9
What is the range of these data? ## Exercises

Work out the answers to the questions below and fill in the boxes. Click on the button to find out whether you have answered correctly. If you are right then will appear and you should move on to the next question. If appears then your answer is wrong. Click on to clear your original answer and have another go. If you can't work out the right answer then click on to see the answer.

Question 1
Calculate the range of each of the sets of data below:
 (a) 4 7 6 3 9 12 7 12 Range =  (b) 6 5 5 16 12 21 42 7 Range =  (c) 0 2 4 1 3 0 6 Range =  (d) 3 7 8 9 4 7 11 Range =  Question 2
Look at the vertical line diagram below. What is the range of the data illustrated in the diagram?  Question 3
The heights of 10 students were measured to the nearest centimetre.
The results are below: What is the range for this data?
cm  Question 4
The range of a set of data is 12 and the smallest number in the set of data is 5.

What is the largest number in the set of data?  Question 5
The largest number in a set of data is 86. The range of the set of data is 57.

What is the smallest number in the set of data?  Question 6
Look at this set of temperatures: What is the range?
ºC  Question 7
The range of a set of temperatures is 8 °C. The maximum temperature in the set is 6 °C.

What is the minimum temperature in the set?
ºC  Question 8
The range of a set of temperatures is 7 °C. The minimum temperature in the set is -11 °C.

What is the maximum temperature in the set?
ºC  You have now completed Unit 18 Section 3
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