The owner of Darkest Tans Unlimited in a local mall is forecasting this month's (October's) demand for the one new tanning booth based on the following historical data: $$\begin{array} { l l }
\text { Month } & \text { Number of Visits } \
\hline \text { April } & 100 \
\text { May } & 140 \
\text { June } & 110 \
\text { July } & 150 \
\text { August } & 120 \
\text { September } & 160
\end{array}$$ What is the monthly rate of change (slope) of the least squares trend line for these data?
A) 320
B) 102
C) 8
D) -.4
E) -8

Question

The owner of Darkest Tans Unlimited in a local mall is forecasting this month's (October's) demand for the one new tanning booth based on the following historical data: $$\begin{array} { l l } 
\text { Month } & \text { Number of Visits } \
\hline  \text { April } & 100 \
\text { May } & 140 \
\text { June } & 110 \
\text { July } & 150 \
\text { August } & 120 \
\text { September } & 160
\end{array}$$ What is the monthly rate of change (slope) of the least squares trend line for these data?
A) 320
B) 102
C) 8
D) -.4
E) -8

Quizplus · Accepted Answer

The slope of the least squares trend line is calculated using the formula for the slope of a line, which is the change in y over the change in x. Here, the slope is calculated as the average change in the number of visits per month. By applying the least squares method, the slope is found to be 8.

The Owner of Darkest Tans Unlimited in a Local Mall