Problem $3-21$

Two different forecasting techniques $($F$1$ and F$2)$ were used to forecast demand for cases of bottled water. Actual demand and the two sets of forecasts are as follows:

PREDICTED DEMAND

Period Demand F$1$ F$2$

$1686760$

$2756662$

$3707370$

$4746672$

$5697475$

$6727075$

$7807176$

$8787585$

a$.$ Compute MAD for each set of forecasts. Given your results, which forecast appears to be more accurate? $($Round your answers to $2$ decimal place.$)$

MAD F$15\mathrm{.}00$ Numeric ResponseEdit Unavailable. $5\mathrm{.}00$ correct.

MAD F$25\mathrm{.}38$ Numeric ResponseEdit Unavailable. $5\mathrm{.}38$ correct.

F$1$ Correctappears to be more accurate.

b$.$ Compute the MSE for each set of forecasts. Given your results, which forecast appears to be more accurate? $($Round your answers to $2$ decimal places.$)$

MSE F$134\mathrm{.}25$ Numeric ResponseEdit Unavailable. $34\mathrm{.}25$ incorrect.

MSE F$243\mathrm{.}38$ Numeric ResponseEdit Unavailable. $43\mathrm{.}38$ incorrect.

F$1$ Correctappears to be more accurate.

c$.$ In practice, either MAD or MSE would be employed to compute forecast errors. What factors might lead a manager to choose one rather than the other?

Either one might already be in use, familiar to users, and have past values for comparison. If control charts Correct are used, MSE would be natural; if tracking signals Correct are used, MAD would be more natural.

A and C are correct my two values for B are incorrect please help, answer is not $34\mathrm{.}25$ or $43\mathrm{.}38$