Multiple choice$/$Short answer $($show your answer clearly$)$:

For the first $3$ questions, consider the forecast and actual demand shown below for the past $5$ weeks.

Week Demand Forecast

$18084$

$28587$

$38585$

$49088$

$59490$

$6\mathrm{.}1(3$ pts$.)$ What is the MAD for the forecast?

a$)0$

b$)2\mathrm{.}4$

c$)3$

d$)4\mathrm{.}6$

e$)$ none of the above.

$6\mathrm{.}2(3$ pts$.)$ What is the mean squared error $($MSE$)$ for the forecast?

a$)21\mathrm{.}16$

b$)8$

c$)10$

d$)40$

e$)$ none of the above.

$6\mathrm{.}3(3$ pts$.)$ In which range is the MAPE for the forecast?

a$)<2\mathrm{.}0\%$

b$)2\mathrm{.}03\mathrm{.}0\%$

c$)3\mathrm{.}03\mathrm{.}5\%$

d$)3\mathrm{.}510\%$

e$)>10\%.$

$6\mathrm{.}4(3$ pts$.)$ If you use a moving average forecast to forecast data with an upward trend, then the forecast will generally be

a$)$ too high

b$)$ too low

$6\mathrm{.}5(2$ pts$.)$ Qualitative forecasting approaches are best used

a$)$ when there is a large amount of data and time available to make the forecast.

b$)$ when there is little data or time available to make the forecast.

$6\mathrm{.}6(3$ pts$.)$ At a walk$-$in medical clinic, the time between customer arrivals averages $30$ seconds. On average, a customer spends $4$ minutes at the center. What is the average arrival rate per hour?

a$)15$ per hour.

b$)30$ per hour.

c$)90$ per hour.

d$)120$ per hour.

e$)$ none of the above.

$6\mathrm{.}7(3$ pts$.)$ Suppose that in a waiting line problem, the average time between customer arrivals increases. Then, the arrival rate would be expected to

a$)$ increase.

b$)$ decrease.

c$)$ stay the same.

$6\mathrm{.}8(3$ pts$.)$ At a busy coffee shop, the time between customer arrivals averages $1$ minute. On average, a customer spends $2$ minutes in service receiving their coffee order. What is the average service rate per hour?

a$)3$ per hour.

b$)30$ per hour.

c$)60$ per hour.

d$)180$ per hour

e$)$ none of the above.

$6\mathrm{.}9(2$ pts$.)$ Consider Sales & Operations planning. If the inventory holding cost per unit is very large relative to the costs for hiring and firing employees, then which Sales & Operations plan is likely to have the lower total cost?

a$)$ Chase plan.

b$)$ Level plan.

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For the next $3$ questions, consider a four$-$month sales and operations planning problem with the monthly demand data shown in the table below. Every plan should start and end with $5$ employees and should start $($at the beginning of June$)$ and end $($at the end of September$)$ with $10$ units of inventory. Each employee makes $10$ units per month and each hire costs $$600$ and each layoff $($firing$)$ costs $$400.$

Month Demand $($units$)$

June $80$

July $90$

August $60$

September $90$

$6\mathrm{.}10(3$ pts$.)$ How many employees would there be in July for Level plan?

a$)6.$

b$)7.$

c$)8.$

d$)9.$

e$)$ none of the above

$6\mathrm{.}11(3$ pts$)$ What would be the total inventory $($summed over the $4$ months$)$ for a Level plan?

a$)35$

b$)40$

c$)50$

d$)70$

e$)$ none of the above

$6\mathrm{.}12(2$ pts$)$ How many employees would there be in August for Chase plan?

a$)6.$

b$)7.$

c$)8.$

d$)9.$

e$)$ none of the above