Question

(A review on SAS data management)
The following is a data set of 12 individuals. And we want to relate the heart rate at rest (Y) to kilograms body weight (X).

90 62

87 41

87 63

73 46

73 53

86 55

100 70

75 47

76 49

87 69

79 41

78 48

Write a program in SAS which read the given data set into SAS library.

In your program, create a new data set which is a copy of the first, with the addition of a new variable which represents the weight in pounds (1 kilogram 2.2 pounds). Use “proc print” to view the data for all three variables.

(c) Create a new variable called weight_group which divides the data set into four groups based on the estimated quartiles for the variable weight. The estimated quartiles may be requested using the keywords q1, median, and q3, in the “proc means” statement.

(d) Use “proc freq” to summarize the frequency of subjects in each of the four groups.

(e) Obtain the mean and standard deviation for the heart rate at rest for each of the four groups. Comment on the results.

(f) Produce a scatterplot of the heart rate at rest versus body weight in kilograms. Describe what you see.

(g)Fit a straight line model for heart rate at rest versus body weight in kilograms. Comment on the fit of the line.

Answer 1

code :

data mydata;
input x y;
datalines;
90 62
87 41
87 63
73 46
73 53
86 55
100 70
75 47
76 49
87 69
79 41
78 48
;
run;
proc print data=mydata;
run;
data newdata;
set mydata;
weight_pound=x*2.2;
run;
proc print data=newdata;
run;

/*(c)*/
proc means data=newdata q1 q3 median;
run;

/*(d)*/
proc freq data=newdata;
run;

output:

The SAS System

Obs	x	y	weight_pound
1	90	62	198.0
2	87	41	191.4
3	87	63	191.4
4	73	46	160.6
5	73	53	160.6
6	86	55	189.2
7	100	70	220.0
8	75	47	165.0
9	76	49	167.2
10	87	69	191.4
11	79	41	173.8
12	78	48	171.6

The SAS System

The MEANS Procedure

Variable	Lower Quartile	Upper Quartile	Median
x y weight_pound	75.5000000 46.5000000 166.1000000	87.0000000 62.5000000 191.4000000	82.5000000 51.0000000 181.5000000

The SAS System

The FREQ Procedure

x	Frequency	Percent	Cumulative Frequency	Cumulative Percent
73	2	16.67	2	16.67
75	1	8.33	3	25.00
76	1	8.33	4	33.33
78	1	8.33	5	41.67
79	1	8.33	6	50.00
86	1	8.33	7	58.33
87	3	25.00	10	83.33
90	1	8.33	11	91.67
100	1	8.33	12	100.00

y	Frequency	Percent	Cumulative Frequency	Cumulative Percent
41	2	16.67	2	16.67
46	1	8.33	3	25.00
47	1	8.33	4	33.33
48	1	8.33	5	41.67
49	1	8.33	6	50.00
53	1	8.33	7	58.33
55	1	8.33	8	66.67
62	1	8.33	9	75.00
63	1	8.33	10	83.33
69	1	8.33	11	91.67
70	1	8.33	12	100.00

weight_pound	Frequency	Percent	Cumulative Frequency	Cumulative Percent
160.6	2	16.67	2	16.67
165	1	8.33	3	25.00
167.2	1	8.33	4	33.33
171.6	1	8.33	5	41.67
173.8	1	8.33	6	50.00
189.2	1	8.33	7	58.33
191.4	3	25.00	10	83.33
198	1	8.33	11	91.67
220	1	8.33	12	100.00