Date: Tue, 27 Jan 2004 12:00:24 -0600 Paul R Swank "SAS(r) Discussion" Paul R Swank Re: repeated measures analysis of variance To: lamack lamack text/plain; charset="us-ascii"

The time_1 contrast represents the difference between y1 and y2. Thus, grupo by time_1 is the difference between groups on the difference between y 1 and y2. The second contrast should be time_2, representing the differences between y2 and y3 but seems to be a duplicate of the first one.

Paul R. Swank, Ph.D. Professor, Developmental Pediatrics Medical School UT Health Science Center at Houston

-----Original Message----- From: SAS(r) Discussion [mailto:SAS-L@LISTSERV.UGA.EDU] On Behalf Of lamack lamack Sent: Tuesday, January 27, 2004 6:15 AM To: SAS-L@LISTSERV.UGA.EDU Subject: repeated measures analysis of variance

Dear all, I have a question about repeated measures anova interpretation. Running the sas code bellow I have:

1) The within subject test indicate that the interaction of time and group is significant. The main effect of time is not significant. However, the significant interaction indicates that the groups are changing over time and they are changing in diferent ways.

2)from Tests of Hypotheses for Between Subjects Effects I have a significant diference between gropus.

From sas output, my question is. What is the interpretation for the follwing sas output getting by: repeated time 3 profile/summary?

Contrast Variable: time_1

Source DF Type III SS Mean Square F Value Pr > F

Mean 1 1.2071429 1.2071429 0.50 0.4829 grupo 1 304.0960317 304.0960317 126.80 <.0001 Error 34 81.5428571 2.3983193

Contrast Variable: time_1

Source DF Type III SS Mean Square F Value Pr > F

Mean 1 1.2071429 1.2071429 0.50 0.4829 grupo 1 304.0960317 304.0960317 126.80 <.0001 Error 34 81.5428571 2.3983193

The sas Code.

data test; input id group y1-y3@@; cards; 1 b 82 76 77 2 b 84 79 79 3 b 85 82 82 4 b 76 74 75 5 b 83 82 83 6 b 89 83 85 7 b 85 83 83 8 b 77 76 76 9 b 91 88 91 10 b 86 81 82 11 b 85 82 82 12 b 90 89 89 13 b 84 83 83 14 b 84 82 82 15 b 83 80 80 16 b 78 77 76 17 b 82 80 81 18 b 80 78 79 19 b 81 79 79 20 b 88 84 84 21 b 87 84 85 22 f 75 79 79 23 f 76 77 77 24 f 72 74 73 25 f 80 85 84 26 f 75 78 78 27 f 71 72 71 28 f 69 74 74 29 f 78 80 80 30 f 69 73 73 31 f 72 75 74 32 f 76 79 79 33 f 74 77 77 34 f 73 75 75 35 f 82 85 85 36 f 79 85 84 run;

proc glm data = dados; class group; model y1-y3 = gruop/nouni; repeated time 3 profile/summary; run; run;

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