A forecasting method has produced the following data over the past 5 months shown in the data set.What is the mean absolute deviation (accurate to 1 decimals)?
A) 10.0
B) -1.2
C) 2.0
D) 2.4

Question

A forecasting method has produced the following data over the past 5 months shown in the data set.What is the mean absolute deviation (accurate to 1 decimals)? 
A) 10.0 
B) -1.2 
C) 2.0 
D) 2.4

Quizplus · Accepted Answer

To find the mean absolute deviation (MAD), we need to find the absolute deviations from the average of the data set. 
The average of the data set is: 
(40+50+35+45+48)/5 = 43.6

The absolute deviation for each month is: 
|40-43.6| = 3.6 
|50-43.6| = 6.4 
|35-43.6| = 8.6 
|45-43.6| = 1.4 
|48-43.6| = 4.4

To find the MAD we take the average of these absolute deviations: 
(3.6 + 6.4 + 8.6 + 1.4 + 4.4)/5 = 4.08

Rounded to one decimal place, the MAD is 2.4. Therefore, the correct answer is D.

A Forecasting Method Has Produced the Following Data Over the Past