Question

Carter got the following scores on science tests: 90, 82, 88, 78, 93 What is the mean absolute deviation? A. 4.96 B. 12.00 C. 86.20 D. 88.00

Answer 1

first we find the mean (average)
(90 + 82 + 88 + 78 + 93) / 5 = 431/5 = 86.2

now we find the absolute value of the difference of the data points and the mean

90 - 86.2 = 3.8....| 3.8 | = 3.8
82 - 86.2 = -4.2...| -4.2 | = 4.2
88 - 86.2 = 1.8....| 1.8 | = 1.8
78 - 86.2 = -8.2 | -8.2| = 8.2
93 - 86.2 = 6.8....| 6.8| = 6.8

now we find the mean (average) of those values
(3.8 + 4.2 + 1.8 + 8.2 + 6.8) / 5 = 24.8 / 5 = 4.96 <== the MAD