The following information has been collected on the sales of greeting cards for the past 6 weeks.

Week	Sales ($)
1	85
2	90
3	95
4	110
5	105
6	115

1. Develop a linear trend equation that can be used to forecast sales of greeting cards 
2. Use the linear trend equation developed in part A to forecast sales for week 7. 
3. Forecast the sales for week 7 using a three period weighted moving average with weights of 0.6 (week 6), 0.3 (week 5) and 0.1 (week 4). 
4. Compare and explain why the results in parts B and C are different.