A convenience store recently started to carry a new brand of soft drink. Management is interested in estimating future sales volume to determine whether it should continue to carry the new brand or replace it with another brand. The following table provides the number of cans sold per week. Use both the trend projection with regression and the exponential smoothing$($let a$=0\mathrm{.}4$ with an initial forecast for week $1$ of $579)$ methods to forecast demand for week $.$ Compare these methods by using the mean absolute deviation and mean absolute percent error performance criteria. Does your analysis suggest that sales are trending and if$$ so$,$ by how$$ much?

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Period

$1$

$2$

$3$

$4$

$5$

$6$

$7$

$8$

$9$

$10$

$11$

$12$

Sales

Part $2$

$($i$)$ Obtain the trend projection with regression forecast.

The forecast for week is

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enter your response here. $($Enter your response rounded to the nearest whole$$ number.$)$