Worksheet: The Mean of a Data Set

In this worksheet, we will practice finding the mean of a set of data using it to find missing data.

Q1:

Which of the following data sets has a mean of 59?

  • A52, 76, 23, 50, 15
  • B11, 50, 21, 72, 48
  • C81, 34, 85, 21, 76
  • D74, 79, 27, 59, 56
  • E90, 64, 49, 13, 50

Q2:

In order to get a C in maths, Nabil must have an average score of 70 or more. His test scores so far are 63.3, 85, 79.73, and 70.57. Calculate the minimum score Nabil needs to get on his final test to earn a C.

  • A41.4
  • B53.4
  • C46
  • D51.4
  • E50

Q3:

The table shows the number of subscribers of several internet providers. What is the mean number of subscribers for these internet providers?

Internet Provider Company A Company B Company C
Subscribers (millions) 1.65 1.16 1.9

Q4:

Find, to two decimal places, the mean of the test scores in the table. Then determine which group’s score is closest to the mean.

Class Group Group A Group B Group C Group D Group E Group F Group G Group H
Test Score 78 86 72 93 92 84 87 70
  • A The mean is 82.75, and Group G is the closest to the mean.
  • B The mean is 82.75, and Group E is the closest to the mean.
  • C The mean is 84.57, and Group F is the closest to the mean.
  • D The mean is 82.75, and Group F is the closest to the mean.
  • E The mean is 94.57, and Group D is the closest to the mean.

Q5:

Find the mean of the following set of data: 9.2, 2.5, 1.7, 2.2, 6.4, 9.1, 2.2, 5.9. If necessary, round your answer to the nearest tenth.

Q6:

Adam has the following data: 18, , 11, 15.

If the mean is 13, find the value of .

Q7:

What is the mean of the following numbers: 6, 4, 5, 3, 5, 1?

Q8:

Given that the mean of the side lengths of a triangle is 150 cm, determine its perimeter.

Q9:

Calculate the mean of the values in the table.

17 25 13 22 15 17 24 21 23 14 19 22 19 16 18

Q10:

Find the mean of the values 15, 20, 37, 43, 13, 34, 41, and 39.

Q11:

Given that the mean of the values 2 , 1 3 , 4 , 2 5 , 6 , a n d 𝑎 is 11, find the value of 𝑎 .

Q12:

Calculate the mean of the values given in the table.

136 136 139 135 117 135 120 125 116 131

Q13:

Find the mean of the following set of data: 5.53, 7.74, 8.91, 4.31, 3.22.

Q14:

Determine the mean of three numbers which sum to 42.

Q15:

Find, to the nearest cent, the mean of the set of costs in the table.

Cost Tally Frequency
$12.64 11
$18.06 15
$10.50 10

Q16:

Find the mean of the set of data in the line plot. If necessary, write your answer to the nearest tenth.

Q17:

Before the last soccer game of the season, Karim scored a total of 23 goals. He scored 5 goals in the final game, with an average of 4 goals per game this season. To calculate the total number of games Karim played, we first find the sum of 23 and 5. What would be the next step?

  • Asubtract 4 from 230
  • Badd the sum to 4
  • Cmultiply the sum by 4
  • Ddivide the sum by 4
  • Edivide the sum by 5

Q18:

Given the mean of the values 8, 22, 4, 12, and 𝑋 is 15, find the value of 𝑋 .

Q19:

A student’s mean score in four tests is 35 marks. After he takes a fifth test, his mean score increases to 37 marks. What was his score on the fifth test?

  • A50 marks
  • B36 marks
  • C7 marks
  • D45 marks
  • E2 marks

Q20:

The table shows the total precipitation in Arches National Park in January of each year. Calculate the mean January precipitation over the entire period shown in the table.

Year 1,997 1,998 1,999 2,000 2,001 2,002 2,003 2,004
Precipitation (in) 1.09 0.013 0.54 0.80 0.89 0.24 0.11 0.16

Q21:

The mean of the given data set is 7. Find the missing value 𝑥 .

9 6 3 8 5 𝑥

Q22:

Given that the mean of the marks of 9 students is 45, determine the sum of their marks.

Q23:

A student takes five tests: A, B, C, D, and E. Their mean score for tests A, B, and C is 48. Their mean score for tests D and E is 38. Calculate the mean score of all 5 tests.

Q24:

The table shows how much Bassem saved each day. Describe how the mean would be affected if the savings for Monday were not included.

Day Saturday Sunday Monday Tuesday Wednesday Thursday
Amount Saved $11.90 $6.00 $3.70 $3.10 $6.10 $8.10
  • AThe mean would decrease from $11.90 to $6.48.
  • BThe mean would decrease from $7.04 to $6.48.
  • CThe mean would remain unchaged at $6.48.
  • DThe mean would increase from $6.48 to $7.04.
  • EThe mean would increase from $6.48 to $11.90.

Q25:

If the mean age of two people is 50 and one of the people is 54 years old, how old is the other person?

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