In: Statistics and Probability
An agent for a residential real estate company in a large city has the business objective of developing more accurate estimates of the monthly rental cost for apartments. Toward that goal, the agent would like to use the size of an apartment, as defined by square footage to predict the monthly rental cost. The agent selects a sample of 25 apartments in a particular residential neighborhood and collects the following data:
Size (square feet) |
Rent ($) |
850 |
1950 |
1450 |
2600 |
1085 |
2200 |
1232 |
2500 |
718 |
1950 |
1485 |
2700 |
1136 |
2650 |
726 |
1935 |
700 |
1875 |
956 |
2150 |
1100 |
2400 |
1285 |
2650 |
1985 |
3300 |
1369 |
2800 |
1175 |
2400 |
1225 |
2450 |
1245 |
2100 |
1259 |
2700 |
1150 |
2200 |
896 |
2150 |
1361 |
2600 |
1040 |
2650 |
755 |
2200 |
1000 |
1800 |
1200 |
2750 |
(a) Determine the coefficient of determination, r2, and interpret its meaning.
(b) Determine the standard error of the estimate (Syx).
(c) How useful do you think this regression model is for predicting the monthly rent?
(d) Can you think of other variables that might explain the variation in monthly rent?
x | y | (x-x̅)² | (y-ȳ)² | (x-x̅)(y-ȳ) |
850 | 1950 | 81407.50 | 190444.96 | 124513.65 |
1450 | 2600 | 99023.50 | 45624.96 | 67215.65 |
1085 | 2200 | 2532.10 | 34744.96 | 9379.65 |
1232 | 2500 | 9347.02 | 12904.96 | 10982.85 |
718 | 1950 | 174155.98 | 190444.96 | 182118.45 |
1485 | 2700 | 122276.10 | 98344.96 | 109659.65 |
1136 | 2650 | 0.46 | 69484.96 | 179.25 |
726 | 1935 | 167542.86 | 203761.96 | 184767.05 |
700 | 1875 | 189503.50 | 261529.96 | 222622.65 |
956 | 2150 | 32155.66 | 55884.96 | 42391.25 |
1100 | 2400 | 1247.50 | 184.96 | -480.35 |
1285 | 2650 | 22404.10 | 69484.96 | 39455.65 |
1985 | 3300 | 721956.10 | 834664.96 | 776267.65 |
1369 | 2800 | 54606.34 | 171064.96 | 96650.05 |
1175 | 2400 | 1574.50 | 184.96 | 539.65 |
1225 | 2450 | 8042.50 | 4044.96 | 5703.65 |
1245 | 2100 | 12029.70 | 82024.96 | -31412.35 |
1259 | 2700 | 15296.74 | 98344.96 | 38786.05 |
1150 | 2200 | 215.50 | 34744.96 | -2736.35 |
896 | 2150 | 57274.06 | 55884.96 | 56575.25 |
1361 | 2600 | 50931.46 | 45624.96 | 48205.25 |
1040 | 2650 | 9085.90 | 69484.96 | -25126.35 |
755 | 2200 | 144643.30 | 34744.96 | 70891.65 |
1000 | 1800 | 18311.502 | 343864.960 | 79351.648 |
1200 | 2750 | 4183.502 | 132204.960 | 23517.648 |
ΣX | ΣY | Σ(x-x̅)² | Σ(y-ȳ)² | Σ(x-x̅)(y-ȳ) | |
total sum | 28383 | 59660 | 1999747.44 | 3139726.0 | 2130018.80 |
mean | 1135.32 | 2386.40 | SSxx | SSyy | SSxy |
R² = (Sxy)²/(Sx.Sy) = 0.7226 = 72%
.............
SSE= (SSxx * SSyy - SS²xy)/SSxx =
870949.455
std error ,Syx = √(SSE/(n-2)) =
194.595
Syx measures the typical difference between an
apartment's actual rent and the rent predicted by the regression
equation.
................
R2= 72%
so, this regression model is very useful for predicting the monthly rate and std error is also small
............
other variables can be:
parking facility
location of apartment
furniture in apartment
thanks
upvote please