Toyota Motor Corporation is aiming to boost its sales performance in the global automotive market.

Required: Using the historical sales data provided, develop a seasonal sales forecasting model. Use multiple regression analysis. Predict the next year's sales and determine the standard errors of the forecasts.

Historical Sales Data
Sales, millions of liters	Year	Calendar month
2800	1	1
2850	1	2
2900	1	3
2950	1	4
3000	1	5
3050	1	6
3100	1	7
3150	1	8
3200	1	9
3250	1	10
3300	1	11
3350	1	12
3400	2	13
3450	2	14
3500	2	15
3550	2	16
3600	2	17
3650	2	18
3700	2	19
3750	2	20
3800	2	21
3850	2	22
3900	2	23
3950	2	24
4000	2	25
4050	3	26
4100	3	27
4150	3	28
4200	3	29
4250	3	30
4300	3	31
4350	3	32
4400	3	33
4450	3	34
4500	3	35
4550	3	36