Fibre$-$Optic Connector $1$: Techcore is a high$-$tech company located in Fort Worth, Texas. The company produces a part called a fibre$-$optic connector $($FOC$)$ and wants to generate forecasts of the sales of FOCs over time. The company has weekly sales data for the past $265$ weeks. The available variables are contained in the worksheet "FOC$8"$ and defined as follows.

d to be unimportant.

The variable COMPOSITE was added to the model because it was found to be important.

The variable COMPOSITE was dropped from the model even though it was important.

The variable INDUSTRIAL was dropped from the model even though it was important.

$($b$)$ How many variables are in the model

after

step #$5$ of the process? $($Enter a whole number.$)$ Explain what happened in the first and last steps of the process.

In the first step, INDUSTRIAL was identified as the single important variable in predicting SALES. However, the stepwise process identified that when the model the variables COMPOSITE, TRANS, and UTILITY, then INDUSTRIAL was needed. Hence, the variable INDUSTRIAL was the model during the last step, even though, by itself, it is the single important variable in predicting SALES.