Question

The dot plot below shows how many laps each student in Coach Toni's gym class ran one day.

https://media.studyisland.com/pics/150680no19.png

What is the mean absolute deviation of the data set shown?
A. 7
B. 5
C. 12.5
D. 30

Answer 1

step 1 : find the mean
5(4) + 10(2) + 15(2) + 20 + 35 = 20 + 20 + 30 + 20 + 35= 125
125 / 10 = 12.5
step 2 : find the difference between each data value and the mean...(we want the absolute value, so even if the answers are negative, make them positive)
5 - 12.5 = 7.5
5 - 12.5 = 7.5
5 - 12.5 = 7.5
5 - 12.5 = 7.5
10 - 12.5 = 2.5
10 - 12.5 = 2.5
15 - 12.5 = 2.5
15 - 12.5 = 2.5
20 - 12.5 = 7.5
35 - 12.5 = 22.5

step 3 : Now find the average of these numbers
(7.5(5) + 2.5(4) + 22.5) / 10 = (37.5 + 10 + 22.5) / 10 =
69.7 / 10 = 6.97 rounds to 7

mean absolute deviation is 7