The ages of five friends are 11, nine, 12, 10, 11, what is the main absolute deviation of the ages?
To find the mean absolute deviation (MAD) of the ages, we first need to find the mean age.
Mean = (11 + 9 + 12 + 10 + 11) / 5
Mean = 53 / 5
Mean = 10.6
Next, we will find the absolute deviation of each age from the mean:
|11 - 10.6| = 0.4
|9 - 10.6| = 1.6
|12 - 10.6| = 1.4
|10 - 10.6| = 0.6
|11 - 10.6| = 0.4
Now, we will find the mean of these absolute deviations:
MAD = (0.4 + 1.6 + 1.4 + 0.6 + 0.4) / 5
MAD = 4 / 5
MAD = 0.8
Therefore, the main absolute deviation of the ages is 0.8.