QMB 3200 –  Spring 2021   HW #2

 

 

Answer the questions below to the best of your ability. When appropriate, include the Statistix printout in the indicated spot for the problem. When making interpretations, always interpret in the words of the problem (WOP). I have indicated where the TAs will be specifically looking for the words!!! Good luck!

 

PART I – Data Description – Answer these questions for your automobile data as they apply to a simple linear regression analysis that attempts to predict the price of an automobile based on the mileage of the automobile (we will ignore both TRANS and MODEL for the SLR questions)

 

1. Identify the following:

 

Experimental Unit:

 

 

Dependent Variable:

 

 

Independent Variable:

 

 

Provide the Quiz 4 printout necessary for conducting a SLR analysis of your project data. Use y=price as your dependent variable and x=mileage as your independent variable. Copy and paste the printout here:

 

 

 

 

 

 

 

 

 

 

 

 

 

PART II – Model Interpretations – Answer the following questions about your regression model.

 

2. Is the interpretation of your y-intercept estimate practical for your model? Why or why not?

 

 

3. Interpret the slope interpretation in the words of the problem.

 

 

 

 

4. Interpret the standard deviation of your model in the words of the problem.

 

 

 

 

 

 

 

5. Interpret the Coefficient of Determination (R-squared) in the words of the problem.

 

 

 

 

 

 

6. I want you to conduct the appropriate one–tailed test for predicting the price of an automobile with the mileage variable. Identify the alternative hypothesis (in terms of the β being tested) that you would test and the appropriate p-value to use when conducting this test:

 

H_a:  ____________

 

P-value: _____________

 

 

7. State the appropriate conclusion for your test in the words of the problem. You choose the α to test at.

 

 

 

 

 

 

 

 

 

 

 

 

For the prediction and confidence interval, use the independent variable from observation #5 as your value of X. Copy and paste the printout here (it is the same one I asked for in Quiz 5:

 

8. Give the interpretation for the confidence interval for E(y) shown above in the words of the problem.

 

 

 

9. Answer the questions that are asked in Question 12.38 on page 714 of the text. For ease of answering you can use B’s instead of β’s. For instance, B1 can be used in place of β₁.

a.

 

b.

 

c.