Following information in this table:

Month

Units solds

Price ($)

Advertising

Expenditure ($)

Personal selling

Expenditure ($)

January

2500

3800

28500

43000

February

2250

3700

23500

39000

March

1750

3600

17400

35000

April

1500

3500

15300

34000

May

1000

3200

10400

26000

June

2500

3200

18400

41000

July

2750

3200

28200

40000

August

1750

3000

17400

33000

September

1250

2900

12300

26000

October

3000

2700

29800

45000

November

2000

2700

20300

32000

December

2000

2600

19800

34000

If a linear relationship between units sales, contract price, advertising, and personal selling expenditures from the table above takes the following form:

Where Y is the number of contracts sold, P is the average contract price per month, AD is advertising expenditures, PSE is personal selling expenses, and u is a random disturbance term

1.Estimate that relationship

2.Interpret the estimated parameters