Mean, median, mode and range: find the missing number
key notes :
The range is the difference between the greatest number and the least number.
Learn with an example
Erik has the following data:
11 7 13 7 p 15
If the mean is 10, which number could p be?
- 7
- 13
There are 6 numbers in the group.
Try p = 7.
Find the sum of the numbers.
11 + 7 + 13 + 7 + 7 + 15 = 60
Divide by 6.
60 ÷ 6 = 10
When p = 7, the mean is 10.
Try p = 13.
Find the sum of the numbers.
11 + 7 + 13 + 7 + 13 + 15 = 66
Divide by 6.
66 ÷ 6 = 11
When p = 13, the mean is 11.
The mean is 10, so p = 7.
Bryan has the following data:
3 11 x 18
If the mode is 3, which number could x be?
- 3
- 18
Try x = 3.
Arrange the numbers from least to greatest.
3 3 11 18
The number that appears most often is 3. When x = 3, the mode is 3.
Try x = 18.
Arrange the numbers from least to greatest.
3 11 18 18
The number that appears most often is 18. When x = 18, the mode is 18.
The mode is 3, so x = 3.
Lisa has the following data:
3 2 19 17 11 p
If the mode is 3, which number could p be?
- 11
- 3
Try p = 11.
Arrange the numbers from least to greatest.
2 3 11 11 17 19
The number that appears most often is 11. When p = 11, the mode is 11.
Try p = 3.
Arrange the numbers from least to greatest.
2 3 3 11 17 19
The number that appears most often is 3. When p = 3, the mode is 3.
The mode is 3, so p = 3.
let’s practice!
