A concert promoter is forecasting this year's attendance for one of his concerts based on the following historical data: $$\begin{array} { l l }
\text { Year } & \text { Attendance } \
\hline \text { Four years ago } & 10,000 \
\text { Three years ago } & 12,000 \
\text { Two years ago } & 18,000 \
\text { Last Year } & 20,000
\end{array}$$ The previous trend line had predicted 18,500 for two years ago, and 19,700 for last year. What was the mean absolute deviation for these forecasts?
A) 100
B) 200
C) 400
D) 500
E) 800

Question

A concert promoter is forecasting this year's attendance for one of his concerts based on the following historical data: $$\begin{array} { l l } 
\text { Year } & \text { Attendance } \
\hline \text { Four years ago } & 10,000 \
\text { Three years ago } & 12,000 \
\text { Two years ago } & 18,000 \
\text { Last Year } & 20,000
\end{array}$$ The previous trend line had predicted 18,500 for two years ago, and 19,700 for last year. What was the mean absolute deviation for these forecasts?
A) 100
B) 200
C) 400
D) 500
E) 800

Quizplus · Accepted Answer

The mean absolute deviation is calculated by taking the absolute differences between the actual and forecasted values, summing them, and dividing by the number of observations. The differences are |18,000 - 18,500| = 500 and |20,000 - 19,700| = 300. The mean absolute deviation is (500 + 300) / 2 = 400.

A Concert Promoter Is Forecasting This Year's Attendance for One