I need help with this question. I'm lost.

M2_A2. Western Home Inspections is a home inspection service that provides prospective homebuyers with a thorough assessment of the major systems in a house prior to the execution of the purchase contract. Prospective homebuyers often ask the company for an estimate of the average monthly heating cost of the home during the winter. To answer this question, the company wants to build a regression model to help predict the average monthly heating cost (Y) as a function of the average outside temperature in the winter (X1), the amount of attic insulation in the house (X2), the age of the furnace in the house (X3), and the size of the house measured in square feet (X4). Data on 20 homes has been recorded and is shown in Worksheet A2. The company wants to build a regression model to estimate the average monthly heating cost based on outside temperature, attic insulation, age of the furnace, and size of the house. (Note: I have made some modifications to this problem since creating the supporting video - although it shows a different problem number - it is the solution for this problem). a) Use Excel to do a scatter plot showing the relationship between the heating cost and each of the independent variables. b) If the home inspector wanted to build a regression model using only one independent variable to predict heating cost, which variable should be used? c) Why? d) How do you use the value of Significance F in the model with only one independent variable? e) If the home inspector wanted to build a regression model using two independent variable to predict heating cost, which variable should be added to the model? f) Why? g) If the home inspector wanted to build a regression model using three independent variable to predict heating cost, which variable should be added to the two variable model? h) Why? i) If the home inspector wanted to build a regression model using four independent variable to predict heating cost, which variable should be added to the three variable model? j) Why? k) How do you use the value of Significance F in the model with more than one independent variable? l) Does there appear to be any multicollinearity among the independent variables? m) How can you tell if you have multicollinearity? n) Which sets of variables indicate multicollinearity o) Based on your best model, what is the expected average monthly heating cost for a home which has an average outside temperature of 45, 8 inches of attic insulation, a 7 year old furnace, and is 2000 square foot?

Data set:

Avg Outside Temp Attic Insulation (inches) Age of Furnace (years) Square Footage Avg Heating Cost

29 5 4 1900 198

8 6 7 2800 355

6 10 9 2500 291

22 8 11 2000 230

55 2 4 1300 121

36 2 5 2100 250

28 4 9 2400 360

36 7 2 2300 164

59 5 9 1300 42

64 5 6 1500 90

19 4 8 2300 271

57 5 3 1400 96

39 7 11 1900 187

25 9 8 2100 235

28 6 4 1800 138

53 11 2 1200 71

47 5 2 2000 206

20 4 14 2900 398

39 4 6 2600 319

60 8 6 1500 72