Time__minSquare_FeeRooms 191 2472 177 2361 118 2513 160 1926 177 3029 118 2148 149 2483 178 2940 146 2700 162 1718 112 2387 175 2785 158 3181 160 2078 147 2207 146 2253 149 2173 149 2300 181 2365 197 3229 174 2411 156 2673 241 2593 133 2449 161 2581 160 2146 145 2586 167 3511 146 1592 151 3173 113 2182 165 2017 183 2350 170 2344 151 2330 163 2584 153 3011 163 2543 168 2591 132 1640 148 2242 120 2154 139 1647 125 2199 173 2214 Children 11 13 11 9 12 10 10 13 11 7 12 14 14 8 10 12 10 9 11 15 12 12 15 10 13 9 12 13 7 15 11 7 10 13 10 13 13 13 13 8 11 9 7 9 11 Frequency 1 1 1 1 0 1 1 1 1 1 0 1 1 1 1 1 1 1 1 1 0 1 0 1 1 1 1 1 1 1 0 1 0 1 0 1 1 1 1 1 1 1 1 1 1 1 0 1 0 1 1 1 0 2 1 2 0 2 0 2 0 2 1 2 1 2 0 2 1 2 1 2 0 2 1 2 1 2 0 2 0 2 0 2 0 2 0 2 1 2 QUESTION 1 1. (True or False): We can conclude that having the cleaning service twice or 3 times a month does not have any impact on the amount of time (in minutes) required to clean a house. True False 1 points QUESTION 2 1. Write the SAS codes you will need in order to report the frequency of once-a-month and twice-a-month cleaning services. 1 points 1. QUESTION 3 From the results of stepwise procedure, which variables were left in the model? I. Rooms II. D1_frequency III. D2_frequency IV. Children V. Square Feet VI. Children* D1_frequency VII. Children* D2_frequency All variables Only IV and V Only I, II, V, VI and VII Only I, IV and VI None 1 points QUESTION 4 1. From the results of backwards procedure, which variables were excluded from the model? I. Rooms II. D1_frequency III. D2_frequency IV. Children V. Square Feet VI. Children* D1_frequency VII. Children* D2_frequency All variables Only IV and V Only I, II, V, VI and VII Only VI and VII None 1 points QUESTION 5 1. How many dummy variables are needed for the Frequency variable? 3 2 1 0 1 points QUESTION 6 1. Interaction terms were included in the model in order to test whether kids*frequency affect the amount of time (in minutes) required to clean a house. Complete the regression equation for the model below, where Y=Time (min), x 1=Square Feet, x2=Rooms, x3 =Children, x4 = d1_Frequency x5 = d2_Frequency, x6 = children* d1_Frequency , x7 = children*d2_Frequency (Round to 3 decimal places as needed) Y= + x1 + x2 + x3 + x4 + x5 + x6 + x7 1 points QUESTION 7 1. Using the model with interaction terms, write the Cp procedure in SAS in order to choose the variables to be selected in a new model. 1 points QUESTION 8 1. (True or False) There is multicollinearity in the model with interaction terms. True False 1 points QUESTION 9 1. The percentage of twice-a-month cleaning is _____ (use 2 decimal places) 1 points QUESTION 10 1. Using the p-values, identify which independent variables are significant with alphaequals=0.01. I. Rooms II. D1_frequency III. D2_frequency IV. Children V. Square Feet Only I I and II I, II and III Only children None 1 points QUESTION 11 1. The Coefficient of Determination and SE of the regression line are respectively: 18.61 and 0.36 18.61 and 0.23 19.26 and 0.36 19.26 and 0.29 1 points QUESTION 12 1. Using the model with interaction terms (model in question 15), write the backwards procedure in SAS in order to choose the variables to be selected in a new model. (use = 0.15) 1 points QUESTION 13 1. From the results of CP procedure, which model is the best model? Time = Rooms d1_frequency d2_frequency inter1 inter2 Time = Rooms Children inter1 Time = Rooms Children d1_frequency d2_frequency inter1 inter2 Time = Rooms Children d1_frequency Time = Children d1_frequency d2_frequency inter1 inter2 1 points QUESTION 14 1. (True or False) The model with interaction terms is better than model without interaction terms. True False 1 points QUESTION 15 1. The Coefficient of Determination and SE of the regression line are respectively: 18.61 and 0.36 18.61 and 0.23 19.26 and 0.36 19.26 and 0.29 1 points QUESTION 16 1. Using the model with interaction terms, write the stepwise procedure in SAS in order to choose the variables to be selected in a new model. (use = 0.15 for stay and = 0.10 for entry in the model) 1 points QUESTION 17 1. Write the SAS codes you will need in order to test for multicollinearity. Use the model with interaction variables and use inter1 as variable name of Children* D1_frequency and inter2 as variable name of Children* D2_frequency. 1 points QUESTION 18 1. Write the SAS codes you will need in order to create dummy variables for the Frequency variable. Use once-a-month as comparison group. 1 points QUESTION 19 1. Interpret the meaning of the regression coefficient of the model. Fill in the answer to complete your choice. (Round to two decimal places as needed.) Holding everything constant, a three times a month cleaning the time by compared to a once-a-month frequency. 1 points QUESTION 20 1. The Cp value of the model Time = Children d1_frequency d2_frequency inter1 inter2 is: (SSEp= 22441 and MSEf = 346.28) 6.8 0 7.8 0 8.8 0 5.8 0 1 points 1. QUESTION 21 (True or False): We can conclude that for households with children the average cleaning time is longer than for households that do not have children. True False 1 points QUESTION 22 1. Using SAS, construct a regression model using all of the independent variables. Complete the regression equation for the model below, where Y=Time (min), x1=Square Feet, x2=Rooms, x3 =Children, and x4 = d1_Frequency and x5 = d2_Frequency. (Round to 3 decimal places as needed) Y= + x1 + x2 + x3 + x4 + x5 1 points QUESTION 23 1. Using the p-values, identify which independent variables are significant with alpha = 0.10 I. Rooms II. D1_frequency III. D2_frequency IV. Children V. Square Feet VI. Children* D1_frequency VII. Children* D2_frequency All variables Only I, V, VI and VII Only I, II, V, VI and VII Only VI and VII None 1 points QUESTION 24 1. Using the model without interaction terms, use the Cp procedure in SAS in order to choose the variables to be selected in a new model. Which variables make the best the model? Time = Rooms d1_frequency d2_frequency Time = Rooms Children Time = Rooms Children d1_frequency d2_frequency Time = Rooms Children d1_frequency Time = Children d1_frequency d2_frequency 1 points 1. QUESTION 25 (5 bonus points): Which model do you believe is the best one? Write the model and explain statistically and logically why did you choose this model in particular. Interpret the coefficients. Maximum five short sentences. Instructions\tfor\tHomework\t5\t-\tECN\t410 A\tcleaning\tservice\tsends\tcrews\tto\tresidential\thomes\ton\teither\ta\tonce-a-month,\ttwice-a-month\tschedule or\tthree\ttimes\ta\tmonth,\tdepending\ton\tthe\tcustomer's\tpreference.\tThe\towner\twould\tlike\tto\tpredict\tthe amount\tof\ttime\t(in\tminutes)\trequired\tto\tclean\ta\thouse\tbased\ton\tthe\tsquare\tfootage\tof\tthe\thouse,\tthe total\tnumber\tof\trooms\tin\tthe\thouse,\twhether\tor\tnot\tthe\thousehold\thas\tchildren,\tand\tthe\tfrequency\tof the\tcleaning\tschedule.\tData\tfrom\trandomly\tselected\thomes\tare\tgiven\tin\tSAS\tfile\tCleaning_Service. PLEASE\tuse\tSAS\teditor\tcalled\tSummer_Homework5\t(located\tat\tQ:\\courses\\ECN410\\CoxDornelles)\tto answer\tthe\tquestions. All\thomework\tquestions\trefer\tto\tcleaning_service\tdata\tset. How\tto\twrite\tyour\tSAS\tcodes\tin\tthe\tblank\tspaces: 1) Use\tonly\tlowercases; 2) After\teach\tsemi-colon\tor\t/,\tpress\tenter\tand\tstart\tnew\tline\tof\tcode.\tFor\texample: Right: Space\t1\t-\tdata\tcleaning_service; Space\t2\t-\tset\thw5.cleaningservice; Space\t3\t-\trun; Wrong: Space\t1\t-\tdata\tcleaning_service;set\thw5.cleaningservice;run; Space\t2\t-\tblank Space\t3\t-\tblank Right: Space Space Space Space Space 1 2 3 4 5 - proc reg data = ex3.industrial; model y = x/ lackfit spec; output out = residuals r = yres; run; - proc reg data = ex3.industrial; model y = x/ lackfit spec; output out = residuals r = yres; run; Wrong: Space Space Space Space 1 2 3 4 Space 5 - blank *Please\tnote\tthat\t\"Space\t1\"\tdoes\tnot\tbelong\tto\tSAS\tcodes. 3) When\tcreating\ta\tnew\tdata\tset,\tuse\tthe\tsame\toriginal\tname,\tbut\tinclude\tnumbers\tat\tthe\tend: Example: Space\t1-\tdata\tcleaning_service1; Space\t2\t-\tset\thw5.cleaningservice; Space\t3\t-\trun; *Please\tnote\tthat\t\"Space\t1\"\tdoes\tnot\tbelong\tto\tSAS\tcodes. 4) Do\tnot\twrite\tunnecessary\tcodes.\tFor\texample,\tif\tthe\tquestion\tasks\tabout\tcorrelation,\tdo\tnot include\t\"proc\tgplot\"\talong\twith\tproc\tcorr,\tthat\twill\tmake\tyour\tanswer\twrong. 5) Do\tnot\tinclude\tquotes\tif\tis\tnot\trequired. 6) Leave\tonly\tone\tspace\tbetween\twords.\tHowever,\tdo\tnot\tinclude\tunnecessary\tspaces\tbetween words. Example: Right: Space\t1\t-\tData\tcleaning_service1; Space\t2\t-\tset\thw5.cleaningservice; Space\t3\t-\trun; Wrong: Space\t1\t-\tData cleaning_service1; Space\t2\t-\tset\thw5.cleaningservice; Space\t3\t-\trun; Wrong: Space\t1\t-\tDatacleaning_service1; Space\t2\t-\tset\thw5.cleaningservice; Space\t3\t-\trun; 7) When\tcreating\tdummy\tvariables,\tuse\td1_variablename\tas\tthe\tname\tof\tthe\tfirst\tdummy\tvariable, d2_variablename\tas\tthe\tsecond\tone,\tand\tso\ton. 8) The\tlast\tline\tshould\tbe\tend\twith\trun;\tDo\tnot\tinclude\tQUIT\tas\tpart\tof\tyour\tanswer. 9) Your\tcodes\tshould\tbe\tworking\tin\tSAS.\tIf\tyou\twrite\ta\tcode\twithout\ta\tsemi-colon,\tfor\tinstance,\tit will\tnot\twork\tin\tSAS\tand\tit\twill\tnot\tbe\tgraded. 10) key. Make\tsure\tyou\tuse\tthe\tcodes\tprovided\tin\tthe\tlectures,\tthose\twill\tbe\tthe\tones\tused\tas\tthe\t