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6
How do I calculate mean from a frequency table?
A school recorded the number of days that Year 9 pupils were absent last week.
Calculate the mean number of days absent
To find the mean...
Sum of (number of days x number of pupils) ÷ Number of pupils
100÷200=0.5
Notice that no midpoints are needed as this is not grouped data.
Calculate the mean number of days absent
| Number of days | Number of pupils | No of days x No of pupils |
| 0 | 144 | 0x144=0 |
| 1 | 27 | 1x27=27 |
| 2 | 18 | 2x18=36 |
| 3 | 8 | 3x8=24 |
| 4 | 2 | 4x2=8 |
| 5 | 1 | 5x1=5 |
| Total: | 200 | 100 |
To find the mean...
Sum of (number of days x number of pupils) ÷ Number of pupils
100÷200=0.5
Notice that no midpoints are needed as this is not grouped data.
