[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

# st: Re: Contrasts

 From Edward Ridell To statalist@hsphsun2.harvard.edu Subject st: Re: Contrasts Date Mon, 23 Mar 2009 16:02:00 +0000 (GMT)

```Following this anova:
. anova f sys tc sys*tc

Number of obs =     180     R-squared     =  0.9399
Root MSE      = 1.61981     Adj R-squared =  0.9359

Source |  Partial SS    df       MS           F     Prob > F
-----------+----------------------------------------------------
Model |  6891.18382    11  626.471256     238.77     0.0000
|
sys |  1347.15634     2  673.578172     256.72     0.0000
tc |  4939.60999     3  1646.53666     627.54     0.0000
sys*tc |  604.417487     6  100.736248      38.39     0.0000
|
Residual |  440.796853   168  2.62379079
-----------+----------------------------------------------------
Total |  7331.98067   179  40.9607859
I want to compare systems 1,2 & 3 at time 4. The design matrix is
. test, showorder

Order of columns in the design matrix
1: _cons
2: (sys==1)
3: (sys==2)
4: (sys==3)
5: (tc==1)
6: (tc==2)
7: (tc==3)
8: (tc==4)
9: (sys==1)*(tc==1)
10: (sys==1)*(tc==2)
11: (sys==1)*(tc==3)
12: (sys==1)*(tc==4)
13: (sys==2)*(tc==1)
14: (sys==2)*(tc==2)
15: (sys==2)*(tc==3)
16: (sys==2)*(tc==4)
17: (sys==3)*(tc==1)
18: (sys==3)*(tc==2)
19: (sys==3)*(tc==3)
20: (sys==3)*(tc==4)
and I tried the following:
mat input c2 = (0,0,0,0,0,0,0,0,0,0,0,1,0,0,0,-1,0,0,0,0 \ 0,0,0,0,0,0,0,0,0,0,0,1,0,0,0,0,0,0,0,-1 \ 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,0,0,0,-1)
. test, test(c2)

( 1)  sys*tc - sys*tc = 0
( 2)  sys*tc - sys*tc = 0
( 3)  sys*tc - sys*tc = 0
Constraint 1 dropped
Constraint 2 dropped
Constraint 3 dropped

. test, test(c2) mtest(sidak)
_mtest: 0 valid tests
r(198);

Is there anyway that I can carry out this comparison?
I am usung Stata 10.

Ted.

*
*   For searches and help try:
*   http://www.stata.com/help.cgi?search
*   http://www.stata.com/support/statalist/faq
*   http://www.ats.ucla.edu/stat/stata/
```

 © Copyright 1996–2021 StataCorp LLC   |   Terms of use   |   Privacy   |   Contact us   |   What's new   |   Site index