Homework6Key

# Homework6Key - Spring 2012 STAT 512 HW 6 Key Homework...

This preview shows pages 1–3. Sign up to view the full content.

Spring 2012 STAT 512 HW 6 Key 1 Homework 6 (14.5 pts.) due March 2 A reminder – Please do not hand in any unlabeled or unedited SAS output. Include in your write-up only those results that are necessary to present a complete solution (what you want the grader to grade). In particular, questions must be answered in order (including graphs), and all graphs must be fully labeled (main title should include the question number, and all axes should be labeled). Don’t forget to put all necessary information (see course policies) on the first page. Include the SAS input for all questions at the very end of your homework; this could be important even though it won’t be graded. You will often be asked to continue problems on successive homework assignments so save all your SAS code. 1. (5 pts.) This problem is related to the Assessed valuations, KNNL Problem 8.24 (CH08PR24.DAT). The response variable (Y) is the selling price for the one-family home. X 1 is the assess valuation of the home and X 2 = 1 if the home is on a corner lot and 0 if not. SAS Code: data HW6PR1; infile 'I:\My Documents\Stat 512\CH08PR24.DAT' ; input sell assessed lot; run ; proc print data =HW6PR1; run ; proc sort data = HW6PR1; by assessed; run ; title1 'Assessed Valuations' ; title2 'Scatter plot' ; symbol1 v = N c = black i = rl; symbol2 v = C c = red i = rl; proc gplot data =HW6PR1; plot sell * assessed = lot; run ; data HW6PR1E; set HW6PR1; asslot = assessed * lot; proc reg data =HW6PR1E; model sell = assessed lot asslot/ clb ; sameline: test lot, asslot; run ; quit ; (a) Plot the data for the two populations on the same graph using difference symbols (v = ) and lines. Does the relationship between the selling price and the assessed valuation appear to be the same whether the house is on a corner or not?

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
Spring 2012 STAT 512 HW 6 Key 2 The relationship does not seem to be the same whether the house is on a corner or not. It seems like both the slope and the intercept are different. (b) Run the multiple linear regression with the two explanatory variables and the interaction term. Parameter Standard Variable DF Estimate Error t Value Pr > |t| 95% Confidence Limits Intercept 1 -126.90517 14.72247 -8.62 <.0001 -156.35450 -97.45585 assessed 1 2.77590 0.19628 14.14 <.0001 2.38328 3.16852 lot 1 76.02153 30.13136 2.52 0.0143 15.74985 136.29322 asslot 1 -1.10748 0.40554 -2.73 0.0083 -1.91868 -0.29629 i. Give the equation of the fitted regression line using all three explanatory variables. Y = -126.90517 + 2.77590 X 1 + 76.02153 X 2 – 1.10748 X 1 X 2 ii. Give the equation of the fitted regression line for houses not a corner lot. This is the equation when X 2 = 0 Y = -126.90517 + 2.77590 X 1 iii. Give the equation of the fitted regression line for house on a corner lot. This is the equation when X
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

### Page1 / 12

Homework6Key - Spring 2012 STAT 512 HW 6 Key Homework...

This preview shows document pages 1 - 3. Sign up to view the full document.

View Full Document
Ask a homework question - tutors are online