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Date:         Tue, 27 Sep 2005 18:42:45 +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:      Oneway nested ANOVA & a Split-plot example (for Carlos Arce)
Content-Type: text/plain; charset=ISO-8859-15

Hi Carlos

These examples might help you

* One factor nested ANOVA *. * Inside factor "itype", 4 cages (with 4 rats each one) are nested *.

* Dataset *. DATA LIST FREE/itype cage activ (3 F4.0). BEGIN DATA 1 1 3 1 1 6 1 1 3 1 1 3 1 2 1 1 2 2 1 2 2 1 2 2 1 3 5 1 3 6 1 3 5 1 3 6 1 4 2 1 4 3 1 4 4 1 4 3 2 1 7 2 1 8 2 1 7 2 1 6 2 2 4 2 2 5 2 2 4 2 2 3 2 3 7 2 3 8 2 3 9 2 3 8 2 4 10 2 4 10 2 4 9 2 4 11 END DATA. VAR LABEL itype 'Type of ionization' /activ 'Level of activity'. VALUE LABEL itype 1'Positive' 2'Negative'.

(A) Using UNIANOVA:

ANALYZE: GENERAL LINEAR MODEL: UNIVARIATE: - Dependent variable: activ - Fixed factor: itype - Random factor: cage - PASTE (don't click "OK").

The resulting syntax will be:

UNIANOVA activ BY itype cage /RANDOM = cage /METHOD = SSTYPE(3) /INTERCEPT = INCLUDE /CRITERIA = ALPHA(.05) /DESIGN = itype cage itype*cage .

Last line has to be modified for 2 reasons: - Eliminate the interaction term - Add nesting effect

* Also, some lines are just the default options, and need not be present *.

UNIANOVA activ BY itype cage /RANDOM = cage /DESIGN = itype cage(itype).

RUN: ALL.

(B) Using MIXED:

ANALYZE: MIXED MODELS: LINEAR. - Click CONTINUE - Dependent variable: activ - Factor(s): itype cage - FIXED: itype. ADD. CONTINUE - RANDOM: Select "Build nested terms" and build (using buttons): "cage(itype)" (sorry but I'm unable to explain it with more detail, just play with the mouse) ADD. CONTINUE. - OK.

This the corresponding syntax (after eliminating some lines, as before):

MIXED activ BY itype cage /FIXED = itype | SSTYPE(3) /METHOD = REML /RANDOM cage(itype) | COVTYPE(VC) .

********************************************************************************* * 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'.

* I'll use the syntax (not trying to explain the steps in the P&C interface) *

UNIANOVA yield BY block pcrop nitrogen /RANDOM = block /METHOD = SSTYPE(3) /INTERCEPT = EXCLUDE /TEST= pcrop vs block*pcrop /DESIGN = pcrop block block*pcrop nitrogen pcrop*nitrogen .

As you can see, syntax is needed, unless you want to try Irristat 4.4, a freeware program specifically designed to work with complex agricultural ANOVA models.

Hope this helps you

Marta Garcia-Granero, PhD Statistician


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