The Total Number of Overtime Hours (In 1000s) Worked in a Large

Essay

The total number of overtime hours (in 1000s) worked in a large steel mill was recorded for 16 quarters, as shown below. $$\begin{array} { | c | c | c | } \hline \text { Year } & \text { Quarter } & \text { Overtime hours } \\\hline 2007 & 1 & 20 \\& 2 & 30 \\& 3 & 28 \\& 4 & 20 \\ { 2008 } & 1 & 24 \\& 2 & 34 \\& 3 & 28 \\& 4 & 21 \\{ 2009 } & 1 & 28 \\& 2 & 38 \\& 3 & 31 \\& 4 & 26 \\2010& 1 & 30 \\& 2 & 41 \\& 3 & 35 \\& 4 & 28 \\\hline\end{array}$$ a. Use the regression technique to calculate the linear trend line.
b. Calculate the seasonal indexes based on the regression trend line in part (a).
c. What do the seasonal indexes tell us?