In: Statistics and Probability
ABC Apartments is a 300-unit complex near Fairway University that attracts mostly university students. The manager has collected the following data and wants to project the number of units leased in Semester 9 using simple linear regression. Here is the information that has been collected:
Semester |
University Enrollment (in thousands) |
Average Lease Price ($) |
Number of Units Leased |
1 |
7.2 |
450 |
291 |
2 |
6.3 |
460 |
228 |
3 |
6.7 |
450 |
252 |
4 |
7.0 |
470 |
265 |
5 |
6.9 |
440 |
270 |
6 |
6.4 |
430 |
240 |
7 |
7.1 |
460 |
288 |
8 |
6.7 |
440 |
246 |
In answering these questions, you must identify and use the correct independent and dependent variables.
a) The apartment manager wants to forecast the Number of Units Leased as a function of time. What is the linear regression relationship the manager should use and what is the forecast for the Number of Units Leased for Semester 9?
b) Suppose the manager believes that the Number of Units Leased is a function only of University Enrollment. It is believed that there will be a one semester lag between the enrollment and the units leased. In other words, the number of units leased in a semester is a function of the university enrollment in the prior semester. What is the linear regression relationship the manager should use and what is the forecast for the Number of Units Leased for Semester 9?
c) Suppose the manager believes that the Number of Units Leased is a function only of the Average Lease Price for that semester. What is the linear regression relationship the manager should use and what is the forecast for the Number of Units Leased for Semester 9 if the average lease price for that semester is $450?
d) Considering the strength of each of the relationships that you found in parts a) through c), would you use any of these to forecast the Number of Units Leased for Semester 9? Explain your answer.
a)
independent variable = time/Semester
dependent variable = number of Units lease
Using Excel
data -> data analysis -> regression
SUMMARY OUTPUT | ||||||
Regression Statistics | ||||||
Multiple R | 0.059531178 | |||||
R Square | 0.003543961 | |||||
Adjusted R Square | -0.162532045 | |||||
Standard Error | 24.29473455 | |||||
Observations | 8 | |||||
ANOVA | ||||||
df | SS | MS | F | Significance F | ||
Regression | 1 | 12.5952381 | 12.5952381 | 0.02133939 | 0.88864248 | |
Residual | 6 | 3541.40476 | 590.234127 | |||
Total | 7 | 3554 | ||||
Coefficients | Standard Error | t Stat | P-value | Lower 95% | Upper 95% | |
Intercept | 262.4642857 | 18.9303047 | 13.8647682 | 8.7655E-06 | 216.143499 | 308.785073 |
Semester | -0.547619048 | 3.74875893 | -0.14608009 | 0.88864248 | -9.7205017 | 8.6252636 |
y^ = 262.4643 -0.5476* Semester
= 262.4643 -0.5476* 9
= 257.5357
b)
independent variable = University Enrollment
dependent variable = number of Units lease
y | x |
228 | 7.2 |
252 | 6.3 |
265 | 6.7 |
270 | 7 |
240 | 6.9 |
288 | 6.4 |
246 | 7.1 |
SUMMARY OUTPUT | ||||||
Regression Statistics | ||||||
Multiple R | 0.58741061 | |||||
R Square | 0.34505122 | |||||
Adjusted R Square | 0.21406147 | |||||
Standard Error | 17.9352561 | |||||
Observations | 7 | |||||
ANOVA | ||||||
df | SS | MS | F | Significance F | ||
Regression | 1 | 847.347222 | 847.3472222 | 2.63418482 | 0.16551305 | |
Residual | 5 | 1608.36706 | 321.6734127 | |||
Total | 6 | 2455.71429 | ||||
Coefficients | Standard Error | t Stat | P-value | Lower 95% | Upper 95% | |
Intercept | 488.849206 | 143.890704 | 3.397364752 | 0.0193062 | 118.966376 | 858.732037 |
X Variable 1 | -34.3055556 | 21.1369021 | -1.623017198 | 0.16551305 | -88.6396921 | 20.0285809 |
x = 6.7
y^ = 259.002