A Retailing Outlet Has Been Keeping Daily Sales Records Over

Essay

A retailing outlet has been keeping daily sales records over the past four weeks, as shown below. $$\begin{array}{l}\quad\quad\quad\quad\quad\quad\quad\quad\quad\text { Week }\\\begin{array} { | l | c c c c | } \hline \text { Day } & 1 & 2 & 3 & 4 \\\hline \text { Monday } & 20 & 25 & 22 & 27 \\\text { Tuesday } & 26 & 30 & 26 & 28 \\\text { Wednesday } & 28 & 29 & 29 & 26 \\\text { Thursday } & 34 & 32 & 34 & 31 \\\text { Friday } & 38 & 35 & 37 & 36 \\\hline\end{array}\end{array}$$ a. Use the regression technique to calculate the linear trend line.
b. Calculate the daily indexes based on the regression trend line in part (a).
c. What do the daily indexes tell us?