Problem $5-6$: Quarterly water usage $is$ shown below. $(Please$ calculate

$upto4$ decimal places.$)$

Suppose $we$ obtain the following regression model based $onQ1,Q2,Q3,$ and $Q4$ using the data

$in$ the table above: $,Y=100-{55}^{*}Q1+{20}^{*}Q2+{45}^{*}Q3$

Forecast the quarter $1(Q1)$ water usage for $2025.$

Forecast the quarter $4(Q4)$ water usage for $2030.$

Problem $7-8$: Quarterly water usage $is$ shown below. $(Please$ calculate

$upto4$ decimal places.$)$

Suppose $we$ obtain the following regression model based $onQ1,Q2,Q3,$ and $Q4$ using the data

$in$ the table above: $,Y=160+{10}^{*}t-{130}^{*}Q1-{70}^{*}Q2+{110}^{*}Q3$

Forecast the quarter $1(Q1)$ water usage for $2025.$

Forecast the quarter $4(Q4)$ water usage for $2027.$

Problem $9-10$: Quarterly billing for water usage $is$ shown below. $(Please$

calculate $upto4$ decimal places$)$

Which time series forecasting method best fits the given data?

Forecast the quarter $2(Q2)of$ year $2025.$