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# Linear and quadratic contrasts by day (Trt x day interaction)

Trial had 4 treatments & data collected over multiple days.

When I run the following code (see below), results show a linear effect (trt x day interaction). What do I need to do, to determine which day the linear trend(s) are in?

 Contrasts Label Num DF Den DF F Value Pr > F LINEAR trtXday 1 38.8 14.09 0.0006 QUADRADIC trtXday 1 64.2 0.88 0.3519 CUBIC trtXday 1 77.9 0.01 0.9265

PROC MIXED;

CLASS TRT DAY ID;

MODEL BWkg = TRT|DAY/DDFM=KR;

REPEATED DAY/SUBJECT=ID TYPE = toep;

CONTRAST 'LINEAR trtXday'         trt*day

1.549194  1.161894  0.774597  0.387297  -3.6E-20  -0.3872982         -0.7745967         -1.1618949         -1.5492

0.516398  0.387298  0.258199  0.129099  -1.2E-20  -0.1290994         -0.2581989         -0.3872983         -0.5164

-0.516398 -0.387298 -0.258199 -0.129099 1.2E-20   0.1290994 0.2581989 0.3872983 0.5164

-1.549194 -1.161894 -0.774597 -0.387297 3.6E-20   0.3872982 0.7745967 1.1618949 1.5492;

0.531816  0.132954  -0.151947 -0.322888 -0.379869 -0.322888 -0.151947 0.132954  0.5318

-0.531816 -0.132954 0.151947  0.322888  0.379869  0.322888  0.151947  -0.132954 -0.5318

-0.531816 -0.132954 0.151947  0.322888  0.379869  0.322888  0.151947  -0.132954 -0.5318

0.531816  0.132954  -0.151947 -0.322888 -0.379869 -0.322888 -0.151947 0.132954  0.5318;

CONTRAST 'CUBIC trtXday'          trt*day

0.444949  -0.2224746         -0.4131671         -0.2860388         1.7E-21   0.286039  0.413167  0.222475  -0.4449

-1.334847 0.6674238 1.2395013 0.8581164 -5.1E-21  -0.858117 -1.239501 -0.667425 1.3348

1.334847  -0.6674238         -1.2395013         -0.8581164         5.1E-21   0.858117  1.239501  0.667425  -1.3348

-0.444949 0.2224746 0.4131671 0.2860388 -1.7E-21  -0.286039 -0.413167 -0.222475 0.4449;