Arithmetic mean=4+7+8+9+10+12+13+17÷8=80÷8=10X |D|4 67 38 29 110 012 213 317 7Mean Deviation=£|D|÷N=24÷10=2.4

Mean Deviation about the Mean
- To find the mean deviation about the mean, we first need to calculate the mean of the given data set.
- The mean is calculated by adding up all the numbers in the data set and then dividing by the total number of values.
- For the data set 4, 7, 8, 9, 10, 12, 13, 17, the mean is calculated as follows:
Mean = (4 + 7 + 8 + 9 + 10 + 12 + 13 + 17) / 8
= 80 / 8
= 10

Calculating Deviations
- Next, we calculate the deviation of each value from the mean.
- Deviation is calculated by subtracting the mean from each value in the data set.
- The deviations for the given data set are as follows:
Deviations: (-6), (-3), (-2), (-1), 0, 2, 3, 7

Absolute Deviations
- To find the mean deviation about the mean, we need to consider the absolute deviations.
- Absolute deviation is the absolute value of the deviations calculated earlier.
- The absolute deviations for the given data set are as follows:
Absolute Deviations: 6, 3, 2, 1, 0, 2, 3, 7

Calculating Mean Deviation
- Finally, we calculate the mean deviation by finding the average of all the absolute deviations.
- The mean deviation is calculated by adding up all the absolute deviations and then dividing by the total number of values.
- Mean Deviation = (6 + 3 + 2 + 1 + 0 + 2 + 3 + 7) / 8
= 24 / 8
= 3
Therefore, the mean deviation about the mean for the given data set 4, 7, 8, 9, 10, 12, 13, 17 is 3.