In: Statistics and Probability
A cleaning service sends crews to residential homes on either a once-a-month or twice-a-month schedule, depending on the customer's perference. The owner would like to predict the amount of time, in minutes, required to clean a house based on the square footage of the house, the total number of rooms in the house, the number of bathrooms it has, and the size of the cleaning crew. Complete parts a through d below.
Time Square_Feet Rooms
Bathrooms Crew
131 1546 8 2
3
146 1600 7 1.5
2
131 1629 8 2
3
142 1642 7 1.5
3
143 1710 8 2.5
3
163 1718 7 1.5
3
140 1812 8 2.5
4
162 1929 10 2.5
3
139 1933 8 2.5
3
166 2012 7 2.5
2
147 2015 8 2.5
3
78 2038 10 2.5
4
148 2049 10 2
3
160 2076 8 2
3
159 2140 10 2
4
120 2148 9 2
2
120 2149 10 3
3
111 2157 9 2.5
2
149 2177 9 2
3
142 2189 12 2.5
3
162 2190 10 2.5
2
115 2191 11 2.5
4
144 2204 11 2.5
3
124 2209 8 2.5
4
146 2210 10 3.5
3
93 2212 9 3 3
172 2214 11 3
4
146 2238 12 3.5
3
132 2257 11 3.5
3
147 2257 13 3.5
3
161 2259 9 3
3
148 2270 10 3
3
143 2271 10 3.5
3
151 2306 8 3
3
151 2335 11 2.5
3
183 2348 10 2.5
2
171 2350 14 3
3
179 2364 13 3
2
179 2367 10 4
2
109 2381 11 3.5
4
174 2405 11 4
3
159 2408 11 3
3
133 2447 11 3
3
208 2457 11 3
2
192 2464 12 3.5
2
147 2485 9 3.5
3
120 2518 12 4
4
162 2550 13 4
3
114 2564 13 4.5
3
164 2571 12 3.5
3
143 2583 11 3.5
3
164 2590 14 3.5
3
121 2598 11 4.5
4
239 2602 15 4.5
2
168 2602 14 4
3
153 2681 11 3.5
3
147 2706 12 3.5
3
159 2728 11 4
3
172 2771 13 4
2
175 2784 14 4.5
4
177 2881 15 4.5
2
177 2937 14 4
2
155 3010 14 4
3
180 3038 13 4
2
158 3096 14 4.5
3
154 3174 14 4.5
2
160 3187 15 4.5
3
196 3230 15 4.5
2
161 3319 14 4.5
3
165 3518 13 4.5
3
a. Construct a regression model using all the independent variables. Let ModifyingAbove y with carety be the predicted time in minutes, x1 be the square feet, x2 be the number of rooms, x3 be the number of bathrooms, and x4 be the size of the crew.
y=_+(_)x1+(_)x2+(_)x3+(_)x4
b. calculate the multiple coefficient of determination
c.Test the significance using .05
4. calculate the adjusted multiple coefficient of determination
Using Excel
data -> data analysis -> regression
Result
SUMMARY OUTPUT | |||||
Regression Statistics | |||||
Multiple R | 0.619836494 | ||||
R Square | 0.38419728 | ||||
Adjusted R Square | 0.346301728 | ||||
Standard Error | 20.76535462 | ||||
Observations | 70 | ||||
ANOVA | |||||
df | SS | MS | F | Significance F | |
Regression | 4 | 17486.57453 | 4371.643632 | 10.13832123 | 1.9353E-06 |
Residual | 65 | 28027.9969 | 431.1999523 | ||
Total | 69 | 45514.57143 | |||
Coefficients | Standard Error | t Stat | P-value | Lower 95% | |
Intercept | 164.6632982 | 22.17538133 | 7.425500188 | 3.05951E-10 | 120.3760036 |
Square_Feet | 4.56696E-05 | 0.013063098 | 0.003496074 | 0.99722125 | -0.026043138 |
Rooms | 4.133837156 | 2.056855368 | 2.009785044 | 0.048608405 | 0.026013329 |
Bathrooms | -0.67161431 | 6.069046876 | -0.110662238 | 0.912225176 | -12.79233789 |
Crew | -19.23285449 | 4.157670955 | -4.6258722 | 1.82888E-05 | -27.53629676 |
a) y^ = 164.6633 + 0.00004567 Square_feet + 4.133837* rooms -0.6716*Bathrooms -19.2329 Crew
b) R^2 =
0.38419728 |
c) Significance F = 1.9353E-06 < 0.05
hence the model is overall significant
d) adjusted R^2 = 0.346301728
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