need this solved with graphs and all.

The following data show the quarterly sales of the 6x* tents for three years at a sporting goods store.

The store owner wants to forecastthe quarterly sales for the next year .

(a) Construct a time series plot. What type of pattern exists in the data?

(b)Use dummy variables and the Excel Regression tool to find a multiple regression model that accounts for seasonal effects in the data.

(c) Based on this model, estimate the quarterly sales for the fourth year.

Year

Quarter

Q1

Q2

Q3

Sales

1

1

1

0

0

71

1

2

0

1

0

49

1

3

0

0

1

58

1

4

0

0

0

78

2

1

1

0

0

68

2

2

0

1

0

41

2

3

0

0

1

60

2

4

0

0

0

81

3

1

1

0

0

62

3

2

0

1

0

51

3

3

0

0

1

53

3

4

0

0

0

72