Chapter 4 Supplemental Homework

For this assignment you will be using the data found in the file
“Archive.xlsx” found on Canvas.
1. Choose three variables that you find interesting.
2. Choose ONE of these three variables to use as a response.
3. Use boxplots to remove outliers from all three variables.
4. Use regression on each of the potential explanatory variables (there should be only 2 here) to compute residuals. Then use those residuals to make boxplots to identify additional outliers. Remove these outliers ONLY FROM THE EXPLANATORY VARIABLES. Do not delete from the response variable this time.
5. Once you have removed all outliers, you can begin your analysis.  Start with scatterplots of each explanatory variables (remember,
you have 2 of these), using the same response variable. Describethe shape of the scatterplots. Does there appear to be any linear association?
6. Compute the coefficient of determination for each explanatory variable with the response variable. Compare the two values.
7. Graph the x-values vs. residuals plot for each explanatory variable with the response variable. Compare the shapes of the two graphs.
8. Of the two potential explanatory variables, which do you think will provide more reliable predictions?
9. Using the explanatory variable you have chosen from number 8, calculate the equation for the line of best fit (least squares regression equation).
10. What is the initial value you found in number 9? What does it mean in this context?
11.What is the rate of change you found in number 9? What does it mean in this context?
12. Using the model from number 9, make predictions about yourselves. Do these predictions resemble reality at all? Why might the predictions not be very accurate?