In: Statistics and Probability
The following data represents the square footage and rent of
apartments in the boroughs of Queens, New York.
Queens (New York City)
Square Footage | Rent Per Month |
---|---|
500 | 650 |
588 | 1215 |
1000 | 2000 |
688 | 1655 |
825 | 1250 |
460 |
1805 |
1259 | 2700 |
650 | 1200 |
560 | 1250 |
1073 | 2350 |
1452 | 3300 |
1305 | 3100 |
a. Find the least-squares regression line, treating square
footage as the explanatory variable.
b. Interpret the slope and y-intercept, if appropriate.
c. Is the rent on the 825-square-foot apartment in the data above
or below the average among 825-square-foot apartments?
d. Suppose a 900-square-foot apartment in Astoria (Queens) has a
residual of −20. Interpret what this means.
using excel>data>data analsysis>Regression
we have
SUMMARY OUTPUT | ||||||||
Regression Statistics | ||||||||
Multiple R | 0.909287 | |||||||
R Square | 0.826803 | |||||||
Adjusted R Square | 0.809483 | |||||||
Standard Error | 364.7004 | |||||||
Observations | 12 | |||||||
ANOVA | ||||||||
df | SS | MS | F | Significance F | ||||
Regression | 1 | 6349409 | 6349409 | 47.73763 | 4.15E-05 | |||
Residual | 10 | 1330064 | 133006.4 | |||||
Total | 11 | 7679473 | ||||||
Coefficients | Standard Error | t Stat | P-value | Lower 95% | Upper 95% | Lower 95.0% | Upper 95.0% | |
Intercept | -34.3148 | 295.4357 | -0.11615 | 0.909833 | -692.587 | 623.9571 | -692.587 | 623.9571 |
Square Footage | 2.209148 | 0.319738 | 6.909243 | 4.15E-05 | 1.496727 | 2.921569 | 1.496727 | 2.921569 |
we have
a )the least-squares regression line, is
Rent = -34.315 +2.209 *Square footage
b. Interpret the slope : for every one feet increase in the square
footage the rent will increase by $ 2.209
interpretation of intercept is not appropriate because rent cannot be negative
c) for square footage = 825-square-foot
Rent = -34.315 +2.209 *825 = 1788.11
Residual = 1250 -1788.11 = -538.11 so the rent on the
825-square-foot apartment in the data below the average among
825-square-foot
d. Suppose a 900-square-foot apartment in Astoria (Queens) has a
residual of −20 , the rent of a 900-square-foot apartment in
Astoria (Queens) is under estimated