The SAS program below reads and calculates statistics for data on sample of trucks. The prepared data that is read by the program is here.

SAS log of the program.

SAS listing of the program.

Data csladat1;

Infile "C:\Documents and Settings\mfinney\Desktop\fuelecon.dat";

Input drive $ enginesize cylinder transmission $ MPG;

Proc contents;

Proc print;

Data csladat2;

Set csladat1;

Proc means; var mpg;

Proc sort; by transmission;

Proc means; var mpg cylinder; by transmission;

Data csladat3;

Set csladat2;

Proc sort; by cylinder;

Proc freq; tables mpg; by cylinder;

Data csladat4;

Set csladat1;

nlmpg=log(mpg);

If drive="4WD" then alldrive=1;else alldrive=0;

If transmission="Auto" then autotrans=1;else autotrans=0;

Proc reg;

Model mpg=alldrive enginesize autotrans;

Model nlmpg=alldrive enginesize autotrans;

run;

The Data statement opens a module in the SAS program in which you normally perform operations such as read in and define variables, create variables etc. The word “Data” is part of the SAS program language.

The Infile statement is directing SAS to find an external (data) file to be read.

This is the location and filename of the data the program is going to read in.

You define the variable names in the Input statement. Each column of data is considered a variable and is given a name. Remember to have as many names as columns of data. The $ sign indicates to SAS that the variable is non-numeric.

The Set statement brings the variables created within the previous data step (cslastat1) into the new data step (cslastat2).

Proc Means calculates summary statistics for the variable MPG. If the “var MPG” isn’t included, SAS will calculate the statistics for all the numerical variables in the data.

Proc Sort sorts the data by the variable you designate. SAS will divide the data by the two values the transmission variable takes on.

This calculates separate summary statistics for the MPG and cylinder variables by the two different values of transmission.

This if statement creates the dummy variable, alldrive, which equals 1 if the vehicle is four wheel drive and 0 if not.

This runs the linear regression model estimating the determinants of miles per gallon for the vehicles in the sample. The independent variables include the alldrive and autotrans dummy variables we created.

This creates a new variable named nlmpg which is the natural log of the variable mpg. The new name could be anything; it doesn’t have to be nlmpg.

This runs the log/linear regression model in which MPG is logged but all the right-hand-side variables are not logged.

Truck	Name	Drive	Displacement	Cylinders	Transmission	CityMPG
1	C1500 SILVERADO	2WD	4.3	6	Auto	15
2	C1500 SILVERADO	2WD	4.3	6	Manual	15
3	C1500 SILVERADO	2WD	4.8	8	Auto	15
4	C1500 SILVERADO	2WD	4.8	8	Manual	16
5	C1500 SILVERADO	2WD	5.3	8	Auto	11
6	C1500 SILVERADO	2WD	5.3	8	Auto	15
7	C1500 SILVERADO	2WD	5.3	8	Auto	15
8	SSR PICKUP	2WD	5.3	8	Auto	15
9	CHEVY C2500 SILVERADO	2WD	6	8	Auto	10
10	CHEVY C2500 SILVERADO	2WD	6	8	Auto	10
11	C1500 SIERRA	2WD	4.3	6	Auto	16
12	C1500 SIERRA	2WD	4.3	6	Manual	15
13	C1500 SIERRA	2WD	4.8	8	Auto	15
14	C1500 SIERRA	2WD	4.8	8	Manual	16
15	C1500 SIERRA	2WD	5.3	8	Auto	11
16	C1500 SIERRA	2WD	5.3	8	Auto	15
17	C1500 SIERRA	2WD	5.3	8	Auto	15
18	K1500 SILVERADO	4WD	4.3	6	Auto	14
19	K1500 SILVERADO	4WD	4.3	6	Manual	14
20	K1500 SILVERADO	4WD	4.8	8	Auto	14
21	K1500 SILVERADO	4WD	4.8	8	Manual	14
22	K1500 SILVERADO	4WD	5.3	8	Auto	10
23	K1500 SILVERADO	4WD	5.3	8	Auto	13
24	K1500 SILVERADO	4WD	5.3	8	Auto	14
25	S10 PICKUP	4WD	4.3	6	Auto	15
26	S10 PICKUP	4WD	4.3	6	Manual	14
27	K1500 SIERRA	4WD	4.3	6	Auto	15
28	K1500 SIERRA	4WD	4.3	6	Manual	14
29	K1500 SIERRA	4WD	4.8	8	Auto	14
30	K1500 SIERRA	4WD	4.8	8	Manual	14
31	K1500 SIERRA	4WD	5.3	8	Auto	10
32	K1500 SIERRA	4WD	5.3	8	Auto	13
33	K1500 SIERRA	4WD	5.3	8	Auto	14
34	SONOMA	4WD	4.3	6	Auto	15
35	SONOMA	4WD	4.3	6	Manual	14

2WD	5.3	8	Auto	15
2WD	5.3	8	Auto	15
2WD	5.3	8	Auto	15
2WD	6	8	Auto	10
2WD	6	8	Auto	10
2WD	4.3	6	Auto	16
2WD	4.3	6	Manual	15
2WD	4.8	8	Auto	15
2WD	4.8	8	Manual	16
2WD	5.3	8	Auto	11
2WD	5.3	8	Auto	15
2WD	5.3	8	Auto	15
4WD	4.3	6	Auto	14
4WD	4.3	6	Manual	14
4WD	4.8	8	Auto	14
4WD	4.8	8	Manual	14
4WD	5.3	8	Auto	10
4WD	5.3	8	Auto	13
4WD	5.3	8	Auto	14
4WD	4.3	6	Auto	15
4WD	4.3	6	Manual	14
4WD	4.3	6	Auto	15
4WD	4.3	6	Manual	14
4WD	4.8	8	Auto	14
4WD	4.8	8	Manual	14
4WD	5.3	8	Auto	10
4WD	5.3	8	Auto	13
4WD	5.3	8	Auto	14
4WD	4.3	6	Auto	15
4WD	4.3	6	Manual	14

1 The SAS System 16:40 Friday, April 2, 2010

NOTE: Copyright (c) 2002-2003 by SAS Institute Inc., Cary, NC, USA.

NOTE: SAS (r) 9.1 (TS1M3)

Licensed to CALIFORNIA STATE UNIVERSITY LOS ANGELES - T&R, Site 0039713006.

NOTE: This session is executing on the XP_PRO platform.

NOTE: SAS 9.1.3 Service Pack 4

NOTE: SAS initialization used:

real time 0.17 seconds

cpu time 0.31 seconds

1 Data csladat1;

2 Infile "C:\Documents and Settings\mfinney\Desktop\fuelecon.dat";

3 Input drive $ engine_size cylinder transmission $ MPG;

NOTE: The infile "C:\Documents and Settings\mfinney\Desktop\fuelecon.dat" is:

File Name=C:\Documents and Settings\mfinney\Desktop\fuelecon.dat,

RECFM=V,LRECL=256

NOTE: 35 records were read from the infile "C:\Documents and

Settings\mfinney\Desktop\fuelecon.dat".

The minimum record length was 75.

The maximum record length was 75.

NOTE: The data set WORK.CSLADAT1 has 35 observations and 5 variables.

NOTE: DATA statement used (Total process time):

real time 0.01 seconds

cpu time 0.01 seconds

4 Proc contents;

NOTE: The PROCEDURE CONTENTS printed page 1.

NOTE: PROCEDURE CONTENTS used (Total process time):

real time 0.01 seconds

cpu time 0.01 seconds

5 Proc print;

6

NOTE: There were 35 observations read from the data set WORK.CSLADAT1.

NOTE: The PROCEDURE PRINT printed page 2.

NOTE: PROCEDURE PRINT used (Total process time):

real time 0.00 seconds

cpu time 0.00 seconds

7 Data csladat2;

8 Set csladat1;

NOTE: There were 35 observations read from the data set WORK.CSLADAT1.

2 The SAS System 16:40 Friday, April 2, 2010

NOTE: The data set WORK.CSLADAT2 has 35 observations and 5 variables.

NOTE: DATA statement used (Total process time):

real time 0.00 seconds

cpu time 0.00 seconds

9 Proc means; var mpg;

NOTE: There were 35 observations read from the data set WORK.CSLADAT2.

NOTE: The PROCEDURE MEANS printed page 3.

NOTE: PROCEDURE MEANS used (Total process time):

real time 0.00 seconds

cpu time 0.00 seconds

10 Proc sort; by transmission;

NOTE: There were 35 observations read from the data set WORK.CSLADAT2.

NOTE: The data set WORK.CSLADAT2 has 35 observations and 5 variables.

NOTE: PROCEDURE SORT used (Total process time):

real time 0.00 seconds

cpu time 0.00 seconds

11 Proc means; var mpg cylinder; by transmission;

12

NOTE: There were 35 observations read from the data set WORK.CSLADAT2.

NOTE: The PROCEDURE MEANS printed page 4.

NOTE: PROCEDURE MEANS used (Total process time):

real time 0.01 seconds

cpu time 0.01 seconds

13 Data csladat3;

14 Set csladat2;

NOTE: There were 35 observations read from the data set WORK.CSLADAT2.

NOTE: The data set WORK.CSLADAT3 has 35 observations and 5 variables.

NOTE: DATA statement used (Total process time):

real time 0.00 seconds

cpu time 0.00 seconds

15 Proc sort; by cylinder;

NOTE: There were 35 observations read from the data set WORK.CSLADAT3.

NOTE: The data set WORK.CSLADAT3 has 35 observations and 5 variables.

NOTE: PROCEDURE SORT used (Total process time):

real time 0.01 seconds

cpu time 0.00 seconds

3 The SAS System 16:40 Friday, April 2, 2010

16 Proc freq; tables mpg; by cylinder;

17

NOTE: There were 35 observations read from the data set WORK.CSLADAT3.

NOTE: The PROCEDURE FREQ printed pages 5-6.

NOTE: PROCEDURE FREQ used (Total process time):

real time 0.01 seconds

cpu time 0.01 seconds

18 Data csladat4;

19 Set csladat1;

20 nlmpg=log(mpg);

21 If drive="4WD" then all_drive=1;else all_drive=0;

22 If transmission="Auto" then auto_trans=1;else auto_trans=0;

23

24

NOTE: There were 35 observations read from the data set WORK.CSLADAT1.

NOTE: The data set WORK.CSLADAT4 has 35 observations and 8 variables.

NOTE: DATA statement used (Total process time):

real time 0.01 seconds

cpu time 0.00 seconds

25 Proc reg;

26 Model mpg=all_drive engine_size auto_trans;

27

28 Model nlmpg=all_drive engine_size auto_trans;

29

30

31 run;

NOTE: The PROCEDURE REG printed pages 7-8.

NOTE: PROCEDURE REG used (Total process time):

real time 0.03 seconds

cpu time 0.01 seconds

NOTE: SAS Institute Inc., SAS Campus Drive, Cary, NC USA 27513-2414

NOTE: The SAS System used:

real time 0.37 seconds

cpu time 0.40 seconds