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st: Re: Need help with agriculture split-plot (not Kirk's definition) - got it
From
Marta García-Granero <[email protected]>
To
[email protected]
Subject
st: Re: Need help with agriculture split-plot (not Kirk's definition) - got it
Date
Mon, 18 Feb 2013 18:15:37 +0100
(ashamed)
Sorry, I found out for myself, I had forgotten the dash (/):
anova chloro blocks nitrogen/blocks#nitrogen years nitrogen#years
Did the trick
"plots" was not needed, after all.
So much to learn yet...
Regards,
Marta
El 18/02/2013 18:00, Marta García-Granero escribió:
Hi:
I am badly stuck trying to translate some SPSS syntax to Stata. I am
trying to set the ANOVA model for an agriculture split-plot, as
described in Kuehl's "Design of Experiments" 2nd ed., chapter 14, with
different error terms for blocks & whole plots factor (error 1), and
sub-plot factor & interaction (error 2).
The closest I got to Table 14.3 is this:
plots blocks nitrogen years chloro
1 1 1 1 3.8
1 1 1 2 5.3
1 1 1 3 5.9
2 2 1 1 3.9
2 2 1 2 5.4
2 2 1 3 4.3
3 1 2 1 5.2
3 1 2 2 5.6
3 1 2 3 5.4
4 2 2 1 6.0
4 2 2 2 6.1
4 2 2 3 6.2
5 1 3 1 6.0
5 1 3 2 5.6
5 1 3 3 7.8
6 2 3 1 7.0
6 2 3 2 6.4
6 2 3 3 7.8
7 1 4 1 6.8
7 1 4 2 8.6
7 1 4 3 8.5
8 2 4 1 7.9
8 2 4 2 8.6
8 2 4 3 8.4
insheet using "kuehlCh14splitplot", double tab
label define source 1 "ureic" 2 "ammonium" 3 "IBDU" 4 "ureic(S)"
label values nitrogen source
label define time 1 "2 years" 2 "5 years" 3 "8 years"
label values years time
anova chloro blocks nitrogen years nitrogen#years plots|blocks#nitrogen
This used to work with SPSS, since it automatically sets as error term
for a given factor any term nested inside it.
The SS, df & MS are correct, but I don't know how to force that the F
values for blocks and nitrogen are computed using
plots|blocks#nitrogenas error term.
My ANOVA table:
Number of obs = 24 R-squared = 0.9648
Root MSE = .463231 Adj R-squared
= 0.8988
Source | Partial SS df MS F Prob > F
----------------------+----------------------------------------------------
Model | 47.0629167 15 3.13752778 14.62 0.0003
|
blocks | .510416667 1 .510416667 2.38 0.1616
nitrogen | 37.3245833 3 12.4415278 57.98 0.0000
years | 3.81583333 2 1.90791667 8.89 0.0093
nitrogen#years | 4.15416667 6 .692361111 3.23 0.0646
plots|blocks#nitrogen | 1.25791667 3 .419305556 1.95 0.1996
|
Residual | 1.71666667 8 .214583333
----------------------+----------------------------------------------------
Total | 48.7795833 23 2.12085145
My goal:
Number of obs = 24 R-squared = 0.9648
Root MSE = .463231 Adj R-squared
= 0.8988
Source | Partial SS df MS F Prob > F
----------------------+----------------------------------------------------
Model | 47.0629167 15 3.13752778
|
blocks | .510416667 1 .510416667 0.510/0.419=1.218
nitrogen | 37.3245833 3 12.4415278
12.442/0.419=29.69
years | 3.81583333 2 1.90791667 8.89 0.0093OK
nitrogen#years | 4.15416667 6 .692361111 3.23
0.0646 OK
plots|blocks#nitrogen | 1.25791667 3 .419305556 --> This
should be Error for blocks&nitrogen
|
Residual | 1.71666667 8 .214583333
----------------------+----------------------------------------------------
Total | 48.7795833 23 2.12085145
Any clues?
Thanks in advance,
Marta GG
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