Date: Wed, 28 Sep 2005 12:16:49 +0200
Reply-To: Marta García-Granero
<biostatistics@terra.es>
Sender: "SPSSX(r) Discussion" <SPSSX-L@LISTSERV.UGA.EDU>
From: Marta García-Granero
<biostatistics@terra.es>
Organization: Asesoría Bioestadística
Subject: Split-plot example with UNIANOVA (syntax) and MIXED (with
Point&Click)
In-Reply-To: <9111183981.20050927184245@terra.es>
Content-Type: text/plain; charset=ISO-8859-15
Following with my yesterday message to Carlos Arce:
Got it finally by myself. They key was not trying to use the /TEST
subcommand, it isn't needed at all.
Marta.
***************************************************************************
* SPLIT-PLOT ANALYSIS USING UNIANOVA (post-hoc wrong for main plot factor)*
* AND MIXED (using EMEANS+SIDAK for correct multiple comparisons) *
* Split-plot example (taken from Irristat 4.4 manual): *
* http://www.irri.org/science/software/irristat.asp *
***************************************************************************
* RESPONSE OF MAIZE TO NITROGEN FERTILIZER *
* WHEN IT IS GROWN AFTER DIFFERENT CROPS *
* TALLEYRAND, H. NCRE CEREALS AGRONOMIST, IRA/GAROUA *
* THE TRIAL WAS A SPLIT PLOT DESIGN WITH PRECEEDING CROP AS *
* MAIN PLOT FACTOR AND FOUR LEVELS OF NITROGEN AS SUB-PLOT *
* FACTOR: 0, 45, 90, 135 KG N/ha. MAIZE VARIETY CMS8501. *
***************************************************************************
* Dataset *.
DATA LIST FREE/block pcrop nitrogen (3 F4.0) yield (F4.2).
BEGIN DATA
1 5 1 2.35 1 5 2 3.29 1 5 3 4.75 1 5 4 6.39 1 1 1 3.76 1 1 2 5.17
1 1 3 6.30 1 1 4 6.82 1 3 1 2.26 1 3 2 5.17 1 3 3 5.88 1 3 4 6.82
1 2 1 3.71 1 2 2 4.70 1 2 3 5.88 1 2 4 6.20 1 4 1 1.41 1 4 2 3.48
1 4 3 4.61 1 4 4 4.70 2 5 1 4.20 2 5 2 5.23 2 5 3 6.64 2 5 4 6.73
2 1 1 5.28 2 1 2 5.84 2 1 3 6.36 2 1 4 7.39 2 3 1 3.49 2 3 2 5.84
2 3 3 6.88 2 3 4 6.78 2 2 1 4.85 2 2 2 5.98 2 2 3 6.73 2 2 4 7.49
2 4 1 3.12 2 4 2 3.59 2 4 3 4.67 2 4 4 6.50 3 5 1 5.34 3 5 2 6.79
3 5 3 7.31 3 5 4 8.20 3 1 1 6.75 3 1 2 8.11 3 1 3 8.30 3 1 4 8.91
3 3 1 4.26 3 3 2 7.17 3 3 3 7.59 3 3 4 8.34 3 2 1 5.57 3 2 2 5.81
3 2 3 6.23 3 2 4 7.69 3 4 1 4.49 3 4 2 5.67 3 4 3 6.93 3 4 4 7.17
4 5 1 3.38 4 5 2 3.85 4 5 3 5.17 4 5 4 5.36 4 1 1 4.18 4 1 2 5.88
4 1 3 6.30 4 1 4 7.14 4 3 1 2.82 4 3 2 4.61 4 3 3 5.73 4 3 4 5.88
4 2 1 4.47 4 2 2 5.17 4 2 3 5.73 4 2 4 6.34 4 4 1 2.73 4 4 2 3.06
4 4 3 4.70 4 4 4 5.36
END DATA.
VALUE LABEL pcrop 1'PPEAS' 2'CROTL' 3'GNUTS' 4'CWPEA' 5'MAIZE'.
VALUE LABEL nitrogen 1'0' 2'45' 3'90' 4'135'.
* Using UNIANOVA (post-hoctests are wrong for 'pcrop', because
MS(error) and df(error) are used, instead of MS(block*pcrop)
and df(block*pcrop) *
UNIANOVA
yield BY block pcrop nitrogen
/RANDOM = block
/METHOD = SSTYPE(3)
/INTERCEPT = EXCLUDE
/TEST= pcrop vs block*pcrop
/POSTHOC = pcrop nitrogen (SIDAK)
/DESIGN = pcrop block block*pcrop nitrogen pcrop*nitrogen .
* With MIXED, with a correct post-hoc analysis for main effects
(Warning: assuming interaction is not significant, but it is
significant, this is only for didactic purposes) *.
MIXED
yield BY pcrop block nitrogen
/FIXED = pcrop nitrogen nitrogen*pcrop | NOINT
/METHOD = REML
/RANDOM = block block*pcrop | COVTYPE(VC)
/SAVE = RESID
/EMMEANS = TABLES(pcrop) COMPARE ADJ(SIDAK)
/EMMEANS = TABLES(nitrogen) COMPARE ADJ(SIDAK) .
****************************************************************
* And now, I promised that: using the P&C interface (Aka: GUI) *
****************************************************************
ANALYZE: MIXED MODELS: LINEAR.
- Click CONTINUE.
- Dependent variable: yield.
- Factor(s): pcrop block nitrogen.
- FIXED: Add one by one the following terms:
pcrop nitrogen pcrop*nitrogen.
CONTINUE.
- RANDOM: Add one by one the following terms:
block block*nitrogen.
CONTINUE.
- EMEANS: Select display means for: pcrop nitrogen
Click 'Compare main effects'
Select 'Confidence interval adjustment:
Sidak (or Bonferroni)
CONTINUE.
- SAVE: Residuals.
CONTINUE.
- OK.
