The sales data for two years are as follows. Data are aggregated with two months of sales in each "period." MONTHS SALES MONTHS SALES January to February 110 January to February 100 March to April 104 March to April 97 May to June 149 May to June 158 July to August 169 July to August 176 September to October 118 September to October 119 November to December 85 November to December 101

Fit a simple linear regression model to the sales data.

Note: Do not round intermediate calculations. Round your final answers to 2 decimal places.

In addition to the regression model, determine multiplicative seasonal index. A full cycle is assumed to be a full year.

Note: Do not round intermediate calculations. Round your and final answers to 2 decimal places.

Prepare sales forecasts for next year using both of your regression models derived above to show results both with and without adjustments for seasonality.

Note: Do not round intermediate calculations. Round your final answers to 1 decimal places.