What is the mean absolute deviation of the data set? (15,16,15,8,6 3 4 10 12

The answer is 4

Using the formula in the attached:
Where: xi = data points or value; x⁻ = mean; n = number of data points or size

1.) Calculate the mean:
x⁻ = 15 + 16 + 15 + 8 + 6 / 5
   = 60 / 5
x⁻ = 12

2.) Calculate absolute difference between mean and data points or value:
15 - 12 = 3
16 - 12 = 4
15 - 12 = 3
  8 - 12 = 4
  6 - 12 = 6

3.) Sum the differences and divide by n:
MAD = 3 + 4 + 3 + 4 + 6 / 5
         = 20 / 5
MAD = 4

There is no association.