the mean is the average,
add the numbers in the set and divide by the quantity of numbers:
9 + 15 + 22 + 45 + 50 +60 + 65 = 266
266 / 7 = 38
the mean = 38
the absolute deviation is subtracting the number from the mean: ( all numbers are positive)
38 - 9 = 29
38 - 15 = 23
38-22 = 16
45-38 = 7
50 -38 = 12
60-38 = 22
65-38 = 27