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st: Re: Using margins
From
Arti Rayit <[email protected]>
To
[email protected]
Subject
st: Re: Using margins
Date
Fri, 4 Feb 2011 15:11:37 +0000 (GMT)
Hello,
I am trying to teach myself how to use margins and I am using a simple oneway
dataset from the manual.
. anova weight treatment
. margins treatment, post asbalanced
. test (1.treatment = 2.treatment) (1.treatment = 3.treatment) (1.treatment =
4.treatment) (2.treatment = 3.treatment) (2.treatment = 4.treatment)
(3.treatment = 4.treatment), mtest(bon)
( 1) 1bn.treatment - 2.treatment = 0
( 2) 1bn.treatment - 3.treatment = 0
( 3) 1bn.treatment - 4.treatment = 0
( 4) 2.treatment - 3.treatment = 0
( 5) 2.treatment - 4.treatment = 0
( 6) 3.treatment - 4.treatment = 0
Constraint 2 dropped
Constraint 4 dropped
Constraint 5 dropped
---------------------------------------
| chi2 df p
-------+-------------------------------
(1) | 63.83 1 0.0000 #
(2) | 16.13 1 0.0004 #
(3) | 17.26 1 0.0002 #
(4) | 9.80 1 0.0105 #
(5) | 8.95 1 0.0167 #
(6) | 0.02 1 1.0000 #
-------+-------------------------------
all | 64.37 3 0.0000
---------------------------------------
# Bonferroni adjusted p-values
Yet when I run the example:
. oneway weight treatment,bon
Analysis of Variance
Source SS df MS F Prob > F
------------------------------------------------------------------------
Between groups 5295.54433 3 1765.18144 21.46 0.0013
Within groups 493.591667 6 82.2652778
------------------------------------------------------------------------
Total 5789.136 9 643.237333
Bartlett's test for equal variances: chi2(3) = 1.3900 Prob>chi2 = 0.708
Comparison of Average weight in grams by Fertilizer
(Bonferroni)
Row Mean-|
Col Mean | 1 2 3
---------+---------------------------------
2 | -59.1667
| 0.001
|
3 | -33.25 25.9167
| 0.042 0.122
|
4 | -34.4 24.7667 -1.15
| 0.036 0.146 1.000
I get completely different adjusted probabilities.
What am I misunderstanding and doing wrong.
Arti
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