Averages

Question 1

Find the mean of these numbers: 5, 10 ,15

Answer 1

Answer: (5 + 10 + 15) ÷ 3 = 30 ÷ 3 = 10

Question 2

What is the mode of these numbers: 3, 6, 3, 9, 3, 12

Answer 2

3

Question 3

What is the median of these numbers: 4, 8, 6, 2, 10

Answer 3

6

Question 4

The mean of 5 numbers is 12. What is the total of the 5 numbers?

Answer 4

Answer: Mean × Number of values = 12 × 5 = 60

Question 5

Find the range of these numbers:
7, 3, 10, 6, 2

Answer 5

Answer: Range = Largest - Smallest = 10 - 2 = 8

Question 6

The ages of 6 students are:
11, 12, 13, 12, 14, 13
Find the mode, median, and range.

Answer 6

Mode = 12 and 13 (both appear twice)
Median = (12 + 13) ÷ 2 = 12.5
Range = 14 - 11 = 3

Question 7

The mean of four numbers is 20. Three of the numbers are 18, 22, and 19. What is the missing number?

Answer 7

Total = 4 × 20 = 80. Known total = 18 + 22 + 19 = 59. Missing number = 80 - 59 = 21

Question 8

A student scores 60, 75, 85, and 80 in four tests. What is their average score?

Answer 8

(60 + 75 + 85 + 80) ÷ 4 = 300 ÷ 4 = 75

Question 9

A data set has a mean of 25. If one value (40) is removed, the new mean is 22. How many values were there at the start?

Answer 9

Let original number of values = n
So, total = 25n. After removing 40, mean becomes 22 → new total = 25n - 40 = 22(n - 1)
Solving:
25n - 40 = 22n - 22
3n = 18 → n = 6

Question 10

Which average is most affected by extreme values (outliers)?

Answer 10

mean