2. Purchasing a Home in Upstate New York A quantitatively savvy,young couple is interested in
purchasing a home in northern New York. They collected data on26 houses that had recently sold in
the area. They want to predict the selling price of homes (inthousands of dollars) based on the size
of the home (in square feet).
The regression equation is: Price ? = -86.097 + 0.248*Size
Regression Statistics
Multiple R 0.745865819
R Square 0.55631582
Adjusted R Square 0.537828979
Standard Error 162.8663093
Observations 26
Coefficients StandardError tStat P-value
Intercept -86.09732282.2443144 -1.0468483 0.30559862
Size 0.247925000.04519506 5.48566590 1.22193E-05
a. What is the correlation of the data set? Use the correlationvalue to help describe the association
shown in the data.
b. Write down the regression equation and then use it to predictthe selling price of a home that is
1,742 square feet in size.
c. One home in the data set is 1,400 square feet and costs$187,000, calculate the residual for this
home.
d. What is the slope of the regression line? Interpret the slopein context.
e. If it would make sense, provide a clear interpretation of theintercept of the regression line, in
context. Otherwise, explain why the interpretation does not makesense.
f. What are the degrees of freedom for constructing a confidenceinterval for, or performing a test
for the effectiveness of the model using slope orcorrelation?
g. Construct and interpret a 95% confidence interval for thepopulation slope.
h. Use the computer output to do a slope test to determinewhether size is an effective linear
predictor of the selling price of recently sold homes. Use asignificance level of 5%. Include and
label all six steps of a formal test of hypothesis forregression using slope.
i. We could also use the value of the sample correlation to finda test statistic and p-value to test the
effectiveness of the model. Use the sample correlation, r, tofind the test statistic and p-value.
Compare these to the results of part h).
j. What is the R2
for this model? Interpret it in context.