To calculate the average deviation from the mean for the dataset {7, 9, 10, 11, 11}, we can follow these steps:
- Calculate the mean.
\[ \text{Mean} = \frac{7 + 9 + 10 + 11 + 11}{5} = \frac{48}{5} = 9.6 \]
- Calculate the absolute deviations from the mean.
- For 7: |7 - 9.6| = 2.6
- For 9: |9 - 9.6| = 0.6
- For 10: |10 - 9.6| = 0.4
- For 11: |11 - 9.6| = 1.4
- For 11: |11 - 9.6| = 1.4 (same value as above)
- Sum the absolute deviations.
\[ \text{Sum of absolute deviations} = 2.6 + 0.6 + 0.4 + 1.4 + 1.4 = 6.4 \]
- Calculate the average deviation.
\[ \text{Average deviation} = \frac{6.4}{5} = 1.28 \]
So, the correct answer is:
The average deviation from the mean is 1.28.