The owner of a cleaning service would like to predict the amount of time, in min
ID: 3360996 • Letter: T
Question
The owner of a cleaning service would like to predict the amount of time, in minutes, required to clean a house (y) based on the square footage of the house (x1), the total number of rooms in the house (x2), the number of bathrooms it has (x3), and the size of the cleaning crew (x4). Data from randomly selected homes can be found in the accompanying table. Complete parts a through e below.
Time (mins) Square Feet Rooms Bathrooms Crew
110 2381 12 3.5 4
112 2159 9 2.5 2
115 2192 11 2.5 4
119 2147 9 3 3
119 2515 11 4 4
125 2208 9 2.5 4
131 1630 8 2 3
132 1548 8 2 3
138 1932 8 2.5 3
140 1814 8 2.5 4
141 1640 7 1.5 3
143 2271 11 3.5 3
144 1711 8 2.5 3
145 2205 10 2.5 3
146 1599 7 1.5 2
146 2015 8 2.5 3
146 2209 10 3.5 3
147 2050 9 2 3
147 2238 11 3.5 3
147 2706 11 3.5 3
148 2256 12 3.5 3
148 2485 10 3.5 3
149 2270 10 3 3
150 2176 10 2 3
152 2334 10 2.5 3
154 2797 14 4 3
154 2679 12 3.5 3
154 3007 13 4 3
158 3097 13 4 .5 3
159 2727 12 4 3
160 2407 11 3 3
160 3188 14 4.5 3
160 3319 14 4.5 3
162 1719 7 1.5 3
162 1927 9 2.5 3
162 2550 13 4 3
163 2188 9 2.5 2
163 2571 13 3.5 3
164 2592 13 3.5 3
165 3517 13 4.5 3
167 2601 13 4 3
170 2351 13 3 3
173 2773 13 4 2
175 2783 14 4.5 4
177 2878 15 4.5 2
178 2936 13 4 2
179 2365 13 3 2
179 3035 12 4 2
197 3230 15 4.5 2
241 2599 15 4.5 2
Time (mins) Square Feet Rooms Bathrooms Crew
a. Use technology to construct a regression model using all the independent variables.Complete the regression model below.
ModifyingAbove y = _____ + ( ) x1 + ( ) x2 + ( ) x3 + ( ) x4
(Round to two decimal places as needed.)
b. Test the significance of each independent variable using alphaequals=0.05.
c. Interpret the p-value for each independent variable.
d. Construct a 95% confidence interval for the regression coefficients for the size of the cleaning crew variable and interpret the meaning.
LCL =
UCL=
e. Using the results from part d, comment on the significance of the size of the cleaning crew variable.
Explanation / Answer
(a)158.61-0.01x1+6.49x2+0.92x3-18.61x4
(b) x2 and x4 are significant as their p-value is less than alpha
(c)x2 and x4 are significant as their p-value is less than alpha=0.05 and p-value of x1 and x3 is more than alpha=0.05, so these two are not significant
(d)LCL=-26.61 and UCL=-10.61
To interpret a confidence interval remember that the sample information is random - but there is a pattern to its behavior if we look at all possible samples. Each possible sample gives us a different sample proportion and a different interval. But, even though the results vary from sample-to-sample, we are "confident" because the margin-of-error would be satisfied for 95% of all samples.
(e)more the size less the time
following information has been generated using ms-excel
Coefficients Standard Error t Stat P-value Intercept 158.6062129 19.91841817 7.962792 3.91E-10 X Variable 1 -0.010627468 0.011029101 -0.96358 0.340404 X Variable 2 6.499432721 2.23394778 2.909393 0.00561 X Variable 3 0.922800628 6.594473338 0.139935 0.889335 X Variable 4 -18.61023143 3.97446572 -4.68245 2.63E-05Related Questions
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