Question

5. Suppose you have a data set:

Experiment 56 880

Control       15 398

Experiment 30 479

Control       18 293

Experiment 35 365

Control       22 984

Control        13 230

Control        20 432

Experiment 34 560

Variables are treatment, weight (g), area (m²), please create a SAS program that:

(A). Reading the data and create a SAS data set;

(b). Create a new variable wt_per_area, using wt_per_area=weight/area and change the unit of weight from g to kg;

(c). Sort the data set by treatment;

(d). Calculate the mean, standard error of weight, area and wt_per_area;

(e). Calculate the mean and standard error for treatment=”experiment” and “control”.

Answer 1

SAS code:

/*create a SAS data set*/
data avi;
input treatment$1-10 weight area;
datalines;
Experiment 56 880
Control 15 398
Experiment 30 479
Control 18 293
Experiment 35 365
Control 22 984
Control 13 230
Control 20 432
Experiment 34 560
;
run;
proc print data=avi;
run;
/*(b)new variable wt_per_area, using wt_per_area=weight/area and change the unit of weight from g to kg*/
data avi3;
set avi;
wt_per_area=weight/(area*1000);
run;
proc print data=avi3;
run;
/*(c)Sort the data set by treatment*/
proc sort data=avi3 out=avi3_sort;
by treatment;
proc print data=avi3_sort;
run;
/*(d)mean, standard error of weight, area and wt_per_area*/
proc means data=avi3_sort;
run;
/*(e) mean and standard error for treatment=”experiment” and “control”*/
proc means data=avi3_sort;
by treatment;
run;

SAS output:

Obs	treatment	weight	area
1	Experiment	56	880
2	Control	15	398
3	Experiment	30	479
4	Control	18	293
5	Experiment	35	365
6	Control	22	984
7	Control	13	230
8	Control	20	432
9	Experiment	34	560

The SAS System

Obs	treatment	weight	area	wt_per_area
1	Experiment	56	880	.000063636
2	Control	15	398	.000037688
3	Experiment	30	479	.000062630
4	Control	18	293	.000061433
5	Experiment	35	365	.000095890
6	Control	22	984	.000022358
7	Control	13	230	.000056522
8	Control	20	432	.000046296
9	Experiment	34	560	.000060714

The SAS System

Obs	treatment	weight	area	wt_per_area
1	Control	15	398	.000037688
2	Control	18	293	.000061433
3	Control	22	984	.000022358
4	Control	13	230	.000056522
5	Control	20	432	.000046296
6	Experiment	56	880	.000063636
7	Experiment	30	479	.000062630
8	Experiment	35	365	.000095890
9	Experiment	34	560	.000060714

The SAS System

The MEANS Procedure

Variable	N	Mean	Std Dev	Minimum	Maximum
weight area wt_per_area	9 9 9	27.0000000 513.4444444 0.000056352	13.5000000 257.4082900 0.000020328	13.0000000 230.0000000 0.000022358	56.0000000 984.0000000 0.000095890

The SAS System

The MEANS Procedure

treatment=Control

Variable	N	Mean	Std Dev	Minimum	Maximum
weight area wt_per_area	5 5 5	17.6000000 467.4000000 0.000044860	3.6469165 299.8829772 0.000015577	13.0000000 230.0000000 0.000022358	22.0000000 984.0000000 0.000061433

treatment=Experiment

Variable	N	Mean	Std Dev	Minimum	Maximum
weight area wt_per_area	4 4 4	38.7500000 571.0000000 0.000070718	11.7011395 220.9841623 0.000016825	30.0000000 365.0000000 0.000060714	56.0000000 880.0000000 0.000095890