1          OPTIONS NONOTES NOSTIMER NOSOURCE NOSYNTAXCHECK;
 70         
 71         /********************* cars2.sas ***************************/
 72         title 'Regression on Metric Cars Data';
 73         
 74         /* Read data directly from Excel spreadsheet */
 75         proc import datafile="/home/brunner0/441s20/mcars4.xlsx"
 76                     out=cars dbms=xlsx replace;
 77                     getnames=yes;
 78         /* Input data file is mcars4.xlsx
 79            Ouput data set is called cars
 80            dbms=xlsx      The input file is an Excel spreadsheet.
 81                           Necessary to read an Excel spreadsheet directly under unix/linux
 82                           Works in PC environment too except for Excel 4.0 spreadsheets
 83                           If there are multiple sheets, use sheet="sheet1" or something.
 84            replace      If the data set cars already exists, replace it.
 85            getnames=yes   Use column names as variable names.                  */
 86         
 
 NOTE: One or more variables were converted because the data type is not supported by the V9 engine. For more details, run with 
       options MSGLEVEL=I.
 NOTE: The import data set has 100 observations and 4 variables.
 NOTE: WORK.CARS data set was successfully created.
 NOTE: PROCEDURE IMPORT used (Total process time):
       real time           0.01 seconds
       user cpu time       0.00 seconds
       system cpu time     0.01 seconds
       memory              2791.81k
       OS Memory           29608.00k
       Timestamp           01/20/2020 02:01:43 AM
       Step Count                        24  Switch Count  2
       Page Faults                       0
       Page Reclaims                     842
       Page Swaps                        0
       Voluntary Context Switches        15
       Involuntary Context Switches      0
       Block Input Operations            0
       Block Output Operations           264
       
 
 87         proc print;
 88              title2 'Look at input data set';
 89         
 
 NOTE: There were 100 observations read from the data set WORK.CARS.
 NOTE: PROCEDURE PRINT used (Total process time):
       real time           0.13 seconds
       user cpu time       0.12 seconds
       system cpu time     0.00 seconds
       memory              2732.09k
       OS Memory           29864.00k
       Timestamp           01/20/2020 02:01:43 AM
       Step Count                        25  Switch Count  1
       Page Faults                       0
       Page Reclaims                     865
       Page Swaps                        0
       Voluntary Context Switches        6
       Involuntary Context Switches      0
       Block Input Operations            0
       Block Output Operations           48
       
 
 90         data auto;
 91              set cars;
 92              mpg = 100/lper100k * 0.6214/0.2642;
 93              Country = Cntry; /* I just like the spelling more */
 94              label Country  = 'Location of Head Office'
 95                    lper100k = 'Litres per 100 kilometers'
 96                    mpg      = 'Miles per Gallon'
 97                    weight   = 'Weight in kg'
 98                    length   = 'Length in meters';
 99         /* Indicator dummy vars: Ref category is Japanese */
 100             if country = 'US' then c1=1;  else c1=0;
 101             if country = 'Europ' then c2=1;  else c2=0;
 102             label c1 = 'US = 1'
 103                   c2 = 'Europe = 1';
 104             /* Interaction Terms */
 105             cw1 = c1*weight; cw2 = c2*weight;
 106         cL1 = c1*length; cL2 = c2*length;
 107        /* This way of creating dummy variables is safe only because
 108           Country is never missing. If it could be missing, better is
 109             if country = ' ' then c1 = .;
 110                else if country = 'US' then c1=1;
 111                else c1=0;
 112             if country =  ' ' then c2 = .;
 113                else if country = 'Europ' then c2=1;
 114                else c2=0;
 115        Note that a blank space is the missing value code for character variables,
 116        while a period is missing for numeric variables.  */
 117        
 
 NOTE: There were 100 observations read from the data set WORK.CARS.
 NOTE: The data set WORK.AUTO has 100 observations and 12 variables.
 NOTE: DATA statement used (Total process time):
       real time           0.00 seconds
       user cpu time       0.01 seconds
       system cpu time     0.00 seconds
       memory              976.28k
       OS Memory           30380.00k
       Timestamp           01/20/2020 02:01:43 AM
       Step Count                        26  Switch Count  2
       Page Faults                       0
       Page Reclaims                     158
       Page Swaps                        0
       Voluntary Context Switches        17
       Involuntary Context Switches      0
       Block Input Operations            0
       Block Output Operations           264
       
 
 118        proc freq;
 119             title2 'Check dummy variables';
 120             tables (c1 c2)*country / norow nocol nopercent;
 121        
 122        /* First an analysis with country only. */
 123        
 124        /* Questions for every significance test:
 125             * What is E(y|x) for the model SAS is using?
 126             * Give the null hypothesis in symbols.
 127             * Do you reject H0 at alpha = 0.05? Answer Yes or No.
 128             * In plain, non-statistical language, what do you conclude? */
 129        
 130        
 
 NOTE: There were 100 observations read from the data set WORK.AUTO.
 NOTE: PROCEDURE FREQ used (Total process time):
       real time           0.04 seconds
       user cpu time       0.04 seconds
       system cpu time     0.00 seconds
       memory              1771.15k
       OS Memory           31152.00k
       Timestamp           01/20/2020 02:01:43 AM
       Step Count                        27  Switch Count  5
       Page Faults                       0
       Page Reclaims                     538
       Page Swaps                        0
       Voluntary Context Switches        27
       Involuntary Context Switches      0
       Block Input Operations            0
       Block Output Operations           528
       
 
 131        proc means;
 132             title2 'Litres per 100 k Broken Down by Country';
 133             class Country;
 134             var lper100k;
 135        
 
 NOTE: There were 100 observations read from the data set WORK.AUTO.
 NOTE: PROCEDURE MEANS used (Total process time):
       real time           0.02 seconds
       user cpu time       0.02 seconds
       system cpu time     0.01 seconds
       memory              9036.65k
       OS Memory           40124.00k
       Timestamp           01/20/2020 02:01:43 AM
       Step Count                        28  Switch Count  2
       Page Faults                       0
       Page Reclaims                     2400
       Page Swaps                        0
       Voluntary Context Switches        35
       Involuntary Context Switches      0
       Block Input Operations            0
       Block Output Operations           24
       
 
 136        proc reg plots = none; /* Suppress diagnostic plots for now*/
 137             title2 'Regression with Just Country';
 138             model lper100k = c1 c2;
 139             USvsEURO: test c1=c2;
 140        
 
 NOTE: PROCEDURE REG used (Total process time):
       real time           0.06 seconds
       user cpu time       0.06 seconds
       system cpu time     0.01 seconds
       memory              2579.96k
       OS Memory           34752.00k
       Timestamp           01/20/2020 02:01:43 AM
       Step Count                        29  Switch Count  2
       Page Faults                       0
       Page Reclaims                     847
       Page Swaps                        0
       Voluntary Context Switches        19
       Involuntary Context Switches      0
       Block Input Operations            0
       Block Output Operations           64
       
 
 141        proc glm;
 142             title2 'Compare Oneway with proc glm';
 143             class country;
 144             model lper100k = country;
 145        
 
 NOTE: PROCEDURE GLM used (Total process time):
       real time           2.56 seconds
       user cpu time       0.12 seconds
       system cpu time     0.02 seconds
       memory              14954.23k
       OS Memory           45240.00k
       Timestamp           01/20/2020 02:01:46 AM
       Step Count                        30  Switch Count  3
       Page Faults                       0
       Page Reclaims                     4304
       Page Swaps                        0
       Voluntary Context Switches        579
       Involuntary Context Switches      0
       Block Input Operations            0
       Block Output Operations           912
       
 
 146        proc reg plots = none data = auto;
 147             title2 'Country, Weight and Length';
 148             model lper100k = c1 c2 weight length;
 149             country: test c1 = c2 = 0;     /* Country controlling for wgt, length */
 150             USvsEURO: test c1=c2;          /* US vs. Europe controlling for wgt, length */
 151             wgt_len: test weight=length=0; /* wgt, length controlling for Country */
 152        
 153        /* Proportions of remaining variation, using a = sF/(n-p+sF) */
 154        
 
 NOTE: PROCEDURE REG used (Total process time):
       real time           0.08 seconds
       user cpu time       0.08 seconds
       system cpu time     0.00 seconds
       memory              2463.31k
       OS Memory           46528.00k
       Timestamp           01/20/2020 02:01:46 AM
       Step Count                        31  Switch Count  2
       Page Faults                       0
       Page Reclaims                     354
       Page Swaps                        0
       Voluntary Context Switches        20
       Involuntary Context Switches      0
       Block Input Operations            0
       Block Output Operations           88
       
 
 155        proc iml;
 NOTE: IML Ready
 156             title2 'Proportion of remaining variation';
 157             print "Country controlling for Weight and Length";
 158             n = 100;
 158      !               p = 5;
 158      !                      s = 2;
 159             F = 6.90;
 159      !                 a = s*F/(n-p + s*F);
 160             print a;
 161        
 162             print "Weight and Length controlling for Country";
 163             F = 115.16;
 163      !                   a = s*F/(n-p + s*F);
 164             print a;
 165        
 NOTE: Exiting IML.
 NOTE: PROCEDURE IML used (Total process time):
       real time           0.01 seconds
       user cpu time       0.02 seconds
       system cpu time     0.00 seconds
       memory              678.21k
       OS Memory           44708.00k
       Timestamp           01/20/2020 02:01:46 AM
       Step Count                        32  Switch Count  1
       Page Faults                       0
       Page Reclaims                     266
       Page Swaps                        0
       Voluntary Context Switches        11
       Involuntary Context Switches      0
       Block Input Operations            0
       Block Output Operations           0
       
 
 166        proc glm data=auto plots=none;
 167             title2 'Country, weight and length with proc glm';
 168             class country;
 169             model lper100k = weight length country;
 170             lsmeans country / pdiff tdiff adjust = bon;
 171        
 
 NOTE: PROCEDURE GLM used (Total process time):
       real time           0.08 seconds
       user cpu time       0.09 seconds
       system cpu time     0.00 seconds
       memory              2293.25k
       OS Memory           46520.00k
       Timestamp           01/20/2020 02:01:46 AM
       Step Count                        33  Switch Count  3
       Page Faults                       0
       Page Reclaims                     340
       Page Swaps                        0
       Voluntary Context Switches        25
       Involuntary Context Switches      0
       Block Input Operations            0
       Block Output Operations           312
       
 
 172        proc reg plots = none;
 173             title2 'Country, Weight and Length with Interactions';
 174             model lper100k = c1 c2 weight length cw1 cw2 cL1 cL2;
 175             country: test c1 = c2 = 0;     /* Is it really still country?  */
 176             Interactions: test cw1 = cw2 = cL1 = cL2 = 0;
 177        
 178        /* Centering an explanatory variable by subtracting off the mean affects the
 179        intercept, but not the relationships among variables. I want to create a new
 180        data set with weight and length centered, and to avoid confusion
 181        I will make sure the variables are nicely labelled. */
 182        
 
 NOTE: PROCEDURE REG used (Total process time):
       real time           0.07 seconds
       user cpu time       0.08 seconds
       system cpu time     0.00 seconds
       memory              2396.28k
       OS Memory           47040.00k
       Timestamp           01/20/2020 02:01:46 AM
       Step Count                        34  Switch Count  2
       Page Faults                       0
       Page Reclaims                     282
       Page Swaps                        0
       Voluntary Context Switches        18
       Involuntary Context Switches      0
       Block Input Operations            0
       Block Output Operations           80
       
 
 183        proc standard mean=0 data=auto out=cntrd;
 184             var weight length;
 185        
 186        /* In the new data set "cntrd," weight and length are adjusted to have mean
 187        zero (the sample means have been subtracted from each observation). If I had
 188        said mean=0 std=1, they would have been converted to z-scores.  All the other
 189        variables (including the product terms) are as they were before, and the
 190        labels are the same as before too. */
 191        
 
 NOTE: The data set WORK.CNTRD has 100 observations and 12 variables.
 NOTE: PROCEDURE STANDARD used (Total process time):
       real time           0.00 seconds
       user cpu time       0.00 seconds
       system cpu time     0.00 seconds
       memory              841.75k
       OS Memory           45740.00k
       Timestamp           01/20/2020 02:01:46 AM
       Step Count                        35  Switch Count  2
       Page Faults                       0
       Page Reclaims                     118
       Page Swaps                        0
       Voluntary Context Switches        14
       Involuntary Context Switches      0
       Block Input Operations            0
       Block Output Operations           264
       
 
 192        data centered;
 193             set cntrd;  /* Now centered has everything in cntrd */
 194            /* Re-create Interaction Terms and re-label explanatory vars*/
 195             cw1 = c1*weight; cw2 = c2*weight;
 196             cL1 = c1*length; cL2 = c2*length;
 197             label weight = 'Weight in kg (Centered)'
 198                   length = 'Length in cm (Centered)';
 199        
 200        /* By default, SAS procedures use the most recently created data set,
 201           but specify it anyway. */
 202        
 
 NOTE: There were 100 observations read from the data set WORK.CNTRD.
 NOTE: The data set WORK.CENTERED has 100 observations and 12 variables.
 NOTE: DATA statement used (Total process time):
       real time           0.00 seconds
       user cpu time       0.00 seconds
       system cpu time     0.01 seconds
       memory              958.03k
       OS Memory           45996.00k
       Timestamp           01/20/2020 02:01:46 AM
       Step Count                        36  Switch Count  2
       Page Faults                       0
       Page Reclaims                     139
       Page Swaps                        0
       Voluntary Context Switches        14
       Involuntary Context Switches      0
       Block Input Operations            0
       Block Output Operations           264
       
 
 203        proc reg plots=none simple data=centered;
 204             title2 'Weight and length are now centered: Mean=0';
 205             model lper100k = c1 c2 weight length cw1 cw2 cL1 cL2;
 206             country: test c1 = c2 = 0;     /* Does this make better sense? */
 207             Interactions: test cw1 = cw2 = cL1 = cL2 = 0;
 208        
 209        quit;
 
 NOTE: PROCEDURE REG used (Total process time):
       real time           0.10 seconds
       user cpu time       0.11 seconds
       system cpu time     0.00 seconds
       memory              2398.71k
       OS Memory           47296.00k
       Timestamp           01/20/2020 02:01:46 AM
       Step Count                        37  Switch Count  2
       Page Faults                       0
       Page Reclaims                     263
       Page Swaps                        0
       Voluntary Context Switches        18
       Involuntary Context Switches      0
       Block Input Operations            0
       Block Output Operations           104
       
 
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 217        OPTIONS NONOTES NOSTIMER NOSOURCE NOSYNTAXCHECK;
 228