**Please show all work** ATTACH EXCEL SHEET OR IF POSSIBLE, USE STATA The quarterly sales of the TRK-50 mountain bike for the previous four years by a bicycle shop in Switzerland is presented in Table 6.8. Use Stata to generate a scatter plot of sales versus time. Next, use Stata to estimate the following model y t =0 + 1 t+ 2 Q 2+ 3 Q3+ 4 Q 4 + t a. From your scatter, what type of trend appears to exist? b. From your scatter, what type of seasonal variation appears to exist? c. Based on your regression results, are all of the independent variables important? d. Write the prediction equation for the model and use it to calculate ^y 17 and ^y 18 . e. Test for positive autocorrelation using the DW statistic with a 5 percent level of significance. y 1. 2. 3. 4. 5. 10 31 43 16 11 6. 7. 8. 9. 10. 33 45 17 13 34 11. 12. 13. 14. 15. 48 19 15 37 51 16. 21