11+ · Topic guide

Averages: Practice Set 2

Averages: Practice Set 2 is a second practice round for 11+ averages questions, revisiting the mean, median, mode and range before moving into harder problems such as finding a missing value from a given mean and combining two data sets.

Year 5-6 (11+)Maths and Numerical ReasoningGL AssessmentCEM

Before you start

Make sure you're comfortable with these topics first:

Method

  1. To find the mean, add up all the values in the data set and divide the total by how many values there are.
  2. To find the median, arrange the values in order from smallest to largest; if there is an even number of values, average the middle two.
  3. The mode is the value that appears most often in the data set; a data set can have more than one mode, or none at all.
  4. The range is found by subtracting the smallest value from the largest value, and describes how spread out the data is.
  5. To find a missing value when you know the mean, multiply the mean by the number of values to find the total, then subtract the sum of the known values.
  6. When combining two data sets, find the total for each set first (mean x number of values), add the totals together, then divide by the combined number of values.

Worked example

Five friends have heights, in cm, of 132, 138, 129, 141 and 135. A sixth friend joins them, and the mean height of all six is now 136 cm. Work out the sixth friend's height.

  1. Add the five known heights: 132 + 138 + 129 + 141 + 135 = 675 cm.
  2. Multiply the new mean by the total number of friends: 136 x 6 = 816 cm.
  3. Subtract the sum of the five known heights from this total: 816 - 675 = 141 cm.
  4. Final answer: 141 cm.

Practice questions

Type your answer and press Check to be marked straight away, or reveal the answer and mark yourself.

Q1Find the mean of 8, 12, 15, 9 and 16.Show answer

Answer: 12

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Q2Find the median of 23, 19, 31, 27 and 15.Show answer

Answer: 23

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Q3Find the mode of 4, 7, 4, 9, 7, 4 and 2.Show answer

Answer: 4

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Q4Find the range of 56, 41, 68, 39 and 72.Show answer

Answer: 33

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Q5The mean of four numbers is 18. Three of the numbers are 14, 22 and 19. Find the fourth number.Show answer

Answer: 17 (18 x 4 = 72, 72 - 55 = 17)

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Q6Six numbers have a mean of 25. A seventh number, 39, is added. Calculate the new mean.Show answer

Answer: 27 (25 x 6 = 150, 150 + 39 = 189, 189 / 7 = 27)

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Exam-style questions

Written in the style of a 11+ exam paper, with a full mark scheme.

Q1[2 marks]

The ages, in years, of five cousins are 11, 14, 9, 16 and 11. Calculate the mean age, giving your answer to 1 decimal place.

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Q2[3 marks]

A netball team's scores in their last 4 matches are 18, 24, 21 and x. The mean score across the 4 matches is 22. (a) Calculate the total of all four scores. (b) Calculate the value of x.

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Q3[4 marks]

Group A has 5 pupils with a mean test score of 64. Group B has 3 pupils with a mean test score of 80. Calculate the mean test score of all 8 pupils combined.

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Free printable worksheet

Want more practice on paper? Download the averages: practice set 2 worksheet pack - 10 pages of exam-style questions with a full mark scheme. One email opens every download in this browser for 14 days - no account, no card. Print it for personal and classroom use.

This topic is chapter 17 of 11+ Maths Workbook 3, the whole course as one free printable PDF.

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