c$-1.$ Calculate the mean absolute deviation $($MAD$)$ for the last nine months of forecasts.

Note: Round your answers to $2$ decimal places.

c$-2.$ Which is best?

multiple choice

Exponential smoothing with trend forecast

Single exponential smoothing forecast

A z value times the lead time in days

The standard deviation of vendor lead time times the standard deviation of demand

The product of lead time in days times the standard deviation of lead time

The product of the standard deviation of demand variability and a z$-$score relating to a specific service probability