In my research, I tested 3 adhesives, my null hypothesis was that the 3 tested adhesives would show no difference in bond strength when applied in 2 different etching modes. I did one-way ANOVA which resulted in significant difference in only one adhesive. Meanwhile the 2-way ANOVA showed the etching factor was significant, the adhesive factor also significant, but the interaction between the 2 factors insignificant...
Two factors are significant partially then their interaction effect must be significant, go with your one way analysis of variance result there is only one adhesive significant.
when you used 2-way ANOVA in this case sime of variation in error go to interaction tear m(MS(inter.); therefore MSE become small than in 1-way ANOVA and this case is correct in result ; but if you go to depene on one-way analysis (each factor analysis partially) MSE contined MS(inter.) and in this point MSE ins larga and not give a good pitcure about our effect factors .
Best Regards
I'm sorry but I think you want to do multiple comparison analysis to determine which is significantly different in the one way setup. I have no idea why you did 2-way ANOVA, please explain. It seems to me that if you did not use 2 adhesives at one time anywhere that 2-way makes no sense. There is no such thing as partially reject. An intro to the many multiple comparisons methods is attached. Best wishes, David Booth
Thank you for your reply and the helpful paper attached. I did the 2 way ANOVA to find out the effect of the etching factor on the adhesive factor . my null hypothesis was that etching wouldn't effect my adhesives. I used my 3 adhesives under the same conditions; with only one variable; etching....
my question is that the fact that there was no interaction between the two factors that I failed to reject my hypothesis?
Well the 2-way anova is one experiment and 1-way anova is a second SEPARATE experiment. You can't use the same data for both ANOVAs. The designs are different. Best, David Booth PS see this reference:
https://www.amazon.com/Analysis-Experiments-Chapman-Statistical-Science/dp/1439868131/ref=sr_1_fkmrnull_1?keywords=John+Lawson+Design+Analysis+Experiments&qid=1557391751&s=books&sr=1-1-fkmrnull
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