$3-$month Period Demand $($units$)$ Jan$-$Mar $20223200$ Apr$-$Jun $20223600$ Jul$-$Sep $20223600$ Oct$-$Dec $20224000$ Jan$-$Mar $20232600$ Apr$-$Jun $20232400$ Jul$-$Sep $20232400$ Oct$-$Dec $20232200$ Using Winter$$s method, calculate the one$-$step and two$-$step demand forecasts for the upcoming two $3-$month periods $($i$.$e$.,$ Jan$-$Mar $2024$ and Apr$-$Jun $2024).$ Show each step of your work. Suppose that the demand for Apr$-$Jun $2024$ turns out to be $2200$ units. What is the MAPE value for your two$-$period$-$ahead forecasts? That means you can only use your Apr$-$Jun $2024$ forecast from part a$.$a$.$ Using Winter's method, calculate the one$-$step and two$-$step demand forecasts for the upcoming two

$3-$month periods $($i$.$e$.,$ Jan$-$Mar $2024$ and Apr$-$Jun $2024).$ Show each step of your work.

b$.$ Suppose that the demand for Jan$-$Mar $2024$ turns out to be $1800$ units. Update the forecasting model

using the following smoothing parameters: $($level$)$ of $0\mathrm{.}3,($trend$)$ of $0\mathrm{.}2,$ and $($seasonality$)$ of $0\mathrm{.}1.$

Using the updated model, forecast the demand for Apr$-$Jun $2024.$

c$.$ Suppose that the demand for Apr$-$Jun $2024$ turns out to be $2200$ units. What is the MAPE value for

your one$-$period$-$ahead forecasts? That means you must use your Jan$-$Mar $2024$ forecast from part a

and Apr$-$Jun $2024$ forecast from part b$.$

d$.$ Suppose that the demand for Apr$-$Jun $2024$ turns out to be $2200$ units. What is the MAPE value for

your two$-$period$-$ahead forecasts? That means you can only use your Apr$-$Jun $2024$ forecast from part

a$.$