topic Re: Linear regression in SAS in SAS Programming

Linear regression in SAS

Joliek44 — Thu, 27 Feb 2020 15:15:32 GMT

Hello,

I am trying to apply linear regression to the data below. Not sure its applicable with the multiple groups in the dosegrp column. Also, I imported the file as CVS. Its original form is excel. Is that why its not working? My file name is HAMA. One of the columns is HAMA. Do I need to change that? I am using SAS 9.4

I have tried using equations in SAS:

proc ree data=work.HAMA;

model dosegrp=hama;

plot dosegrp*hama

getting error: ERROR: Variable dosegrp in list does not match type prescribed for this list.

getting warning: WARNING: No variables specified for an SSCP matrix. Execution terminating

pat_no	dosegrp	HAMA
101	LO	21
104	LO	18
106	LO	19
112	LO	28
116	LO	22
120	LO	30
121	LO	27
124	LO	28
125	LO	19
130	LO	23
136	LO	22
137	LO	20
141	LO	19
143	LO	26
148	LO	35
103	HI	16
105	HI	21
109	HI	31
111	HI	25
113	HI	23
119	HI	25
123	HI	18
127	HI	20
128	HI	18
131	HI	16
135	HI	24
138	HI	22
140	HI	21
142	HI	16
146	HI	33
150	HI	21
151	HI	17
102	PB	22
107	PB	26
108	PB	29
114	PB	19
117	PB	33
118	PB	37
122	PB	25
126	PB	28
129	PB	26
133	PB	31
134	PB	27
139	PB	30
144	PB	25
145	PB	22
147	PB	36
149	PB	32

Re: Linear regression in SAS

PaigeMiller — Thu, 27 Feb 2020 15:38:42 GMT

Mathematically speaking, linear regression requires a continuous Y variable. Your Y variable is not continuous, it is a category. In terms of SAS, the y-variable in linear regression must be numeric, but it is character. So, you have chosen the wrong mathematical method and the wrong SAS procedure.

What you really want is logistic regression, which is appropriate for categorical Y variables.

proc logistic data=work.HAMA;
    model dosegrp=hama;
run;

Re: Linear regression in SAS

Joliek44 — Thu, 27 Feb 2020 18:40:31 GMT

Paige Miller,

Thank you, that is what I was suspecting all along. Its a homework question that i figured was not right. But thank you for the suggestion of logistic regression, I will use that.

Thanks!

Monica