The number of rolls of film processed by a one hour photo finishing Shop has been recorded for the last four years
quarter year 1. Year 2. Year 3. Year 4
1. 942. 1006. 1109. 1243
2. 853. 893. 946. 1067
3. 896. 947. 962. 1102
4. 915. 981. 1051. 1177
Develop the equation for the linear trend component for the time series-trend projection only.