An auditor for a county government would like to develop a model to predict county taxes, based on the age of single-family houses. She selects a random sample of 19 single-family houses, and the results are stored in Taxes.
a. Construct a scatter plot of age and county taxes.
b. Fit a quadratic regression model and state the quadratic regression equation.
c. Predict the county taxes for a house that is 20 years old.
d. Perform a residual analysis on the results and determine whether the regression model is valid.
e. At the 0.05 level of significance, is there a significant overall relationship between age and county taxes?
f. What is the p-value in (e)? Interpret its meaning.
g. At the 0.05 level of significance, determine whether the quadratic model is superior to the linear model.
h. What is the p-value in (g)? Interpret its meaning.
i. Interpret the meaning of the coefficient of multiple determination.
j. Compute the adjusted r2.