How do i slice significant interaction in 2X2 factorial

FestusAdejoro — Tue, 27 Aug 2019 06:28:34 GMT

How do I do slice test for effects when interaction is significant in 2 X 2 factorial

[ New ]

Dear SIr/Ma,

I had tried to analyse a 2 X2 factor experiment with PROC GLM. I reported the P-values for A, B and AB interaction.

My SAS syntax was of this fashion:

proc univariate plot normal;
title 'Trial4Digest';
var v1;
run;
Proc GLM Order = Data;
Class A B;
Model v1 = block A B A*B;
LSmeans A*B/TDIFF PDIFF P STDERR Adjust=tukey;
Run;
Quit;

1. Where interaction was NOT SIGNIFICANT, I had used the simple effect of each factor to compare my means and report in result and discussion.

2. Where interaction was SIGNIFICANT and either FActor A or B is Sig, or FActor A or B is NOT SIGNIFICANT, i had used tukey test to assign "abcd" to the means for comparisons.

	A1		A2			P-values
³Parameter	B-	B+	B-	B+	SEM	A	B	A*B
Ac	58.4	51.5	54.2	55.7	0.71	0.86	0.02	˂0.01
Pro	20.5^b	23.3^a	22.5^a	23.2^a	0.39	0.07	<0.01	0.05
Bu	15.5	18.8	17.5	15.8	0.37	0.40	0.19	˂0.01
Bra	3.66	3.96	3.80	3.30	0.10	0.19	0.54	0.04
Val	1.95^b	2.39^a	1.98^b	2.00^b	0.06	0.02	<0.01	0.01
Ap	3.03^a	2.25^b	2.46^b	2.43^b	0.09	0.175	0.01	0.01

This is the response of the reviewer:

" The use of Tukey's test to separate means is incorrect. Actually, it is not acceptable to use two statistical tests to show a difference between treatments (treatments and interaction effects and mean separation). I greatly discourage the authors from using mean separation when the effect of treatment (factor A, factor B and interaction) is displayed in the tables. A slice test can be used when the interaction is observed. Therefore Tables and text (where appropriate) should be corrected".

I do not have a clue on the way forward on using this slice test and how to interpret the subsequent result. Any help to modify my syntax and report correctly will be appreciated.

Re: How do i slice significant interaction in 2X2 factorial

PaigeMiller — Tue, 27 Aug 2019 14:31:14 GMT

There is a SLICE= option in the LSMEANS statement, that sounds like what you want.

https://documentation.sas.com/?docsetId=statug&docsetTarget=statug_glm_syntax10.htm&docsetVersion=15.1&locale=en#statug.glm.lsmn_opt_slice

topic Re: How do i slice significant interaction in 2X2 factorial in SAS Procedures

How do i slice significant interaction in 2X2 factorial

How do I do slice test for effects when interaction is significant in 2 X 2 factorial

Re: How do i slice significant interaction in 2X2 factorial