In: Operations Management
The quarterly sales data (number of book sold) for Christian book over the past three years in California follow: (You can use Excel to compute the equation)
| 
 Quarter  | 
 Year 1  | 
 Year 2  | 
 Year 3  | 
| 
 1  | 
 1650  | 
 1700  | 
 1750  | 
| 
 2  | 
 950  | 
 800  | 
 1200  | 
| 
 3  | 
 2600  | 
 2950  | 
 3100  | 
| 
 4  | 
 2700  | 
 2450  | 
 2850  | 
Part a) Following is the required chart:

Following pattern is observed by the above chart: Quarter 2 is having the least sales in all the years follwed by quarter 1 then quarter 3 and then quarter 4.
Part b) Following is the formulated data as per requirement and the ANOVA table:
Required Equation from above
regression model is :
Sales = 2666.67 - 966.67*Q1 - 1683.34*Q2 + 216.67*Q3
Next year forecasts are as follows:
Quarter 1 = 1700 units
Quarter 2 = 983 units
Quarter 3 = 2883 units
Quarter 4 = 2667 units
Part c) Following is the formulated data as per requirement and the ANOVA table:

Required Equation from above regression model is :
Sales = 2416.67 + 31.25*t - 872.92*Q1 - 1620.84*Q2 + 247.92*Q3
Next year forecasts are as follows:
Quarter 1 = 1950 units
Quarter 2 = 1233 units
Quarter 3 = 3133 units
Quarter 4 = 2917 units