It seems like you're requesting help with forecasting using seasonal indices and linear regression, and would like the results in an Excel, Word, or PDF format.

Unfortunately, I can't create and send files directly from here, but I can certainly guide you through the process to complete the task, and then you can generate the file yourself.

Steps to solve the problem:

a. Using Seasonal Indices and Linear Regression to Determine the Trend Forecasting Equation:

1. Calculate the overall trend line using linear regression.

   • The trend line is calculated using the equation: $\text{Y} = a + bX$ Where:
     • $Y$ = Forecasted value
     • $a$ = Y-intercept (constant)
     • $b$ = Slope of the line
     • $X$ = Time period (1 to 8 quarters in your case)

   We need to use the demand data from Year 1 and Year 2 for this regression calculation. The independent variable ($X$) will be the quarter number (e.g., 1, 2, 3, 4 for Year 1, etc.) and the dependent variable ($Y$) will be the actual demand.

2. Compute the linear regression equation.

   • You will calculate the slope ($b$) and intercept ($a$) using standard regression formulas or Excel’s built-in functions like LINEST or SLOPE and INTERCEPT.

b. Forecasting Seasonalized Demands for Year 4:

1. Calculate the forecast for each quarter.

   • Once you have the trend line equation, calculate the forecasted demand for each quarter in Year 4.
   • Use the trend equation to find the predicted demand (Y) for each quarter, adjusting the time variable $X$ to represent Year 4 (quarters 1, 2, 3, and 4).

2. Seasonalize the forecast using the seasonal indices.

   • Multiply the forecasted values by the corresponding seasonal index for each quarter:
     • For Quarter 1, use the seasonal index 0.80.
     • For Quarter 2, use the seasonal index 1.05.
     • For Quarter 3, use the seasonal index 0.95.
     • For Quarter 4, use the seasonal index 1.20.

   The formula to compute the seasonalized demand is: $\text{Seasonalized Demand} = \text{Forecasted Demand} \times \text{Seasonal Index}$

If you'd like me to walk you through the process step by step in Excel, feel free to share any data you'd like help with!

Next steps:

1. Would you like me to walk you through how to perform the regression in Excel?
2. Do you need further explanation on how the seasonal indices work in the forecasting equation?
3. Would you like help with interpreting the results once you have completed the calculations?
4. Do you need assistance setting up a template for your forecasts in Excel?
5. Should I clarify how to calculate the trend line formula for linear regression?

Tip:

If you’re using Excel, you can use the LINEST function to get the slope and intercept for the linear regression automatically.