Answer:
2.8
Step-by-step explanation:
1) find the mean of the data set. = 15
2) find the abs value of the diff between each data value and the mean: |data value – mean|.
|10-15|=5, |20-15|=5, |15-15|=0, |17-15|=2, |13-15|=2
3) find the sum of the abs values of the diff = 14
4) divide the sum of the abs value by the number of data values = 14/5 = 2.8