i exposed mussels to different chemicals, same concentrations, different time of exposure, and i got the results for different organs, also i used DMSO as carrier for one chemical, could you please tell me which one is most suitable for mein, ANOVA one way or two way, beside of this i was confused about the effect of carrier how to normalize it (substraction or ratio relative to control) or just see if the difference relative to control is significant or not? thanks in advance
It is not clear what you do measure? You have as sources of variation: chemicals, time of exposure, muscle and an additional factor that is the carrier for one chemical. You may use three way anova table with principal effects and interactions (without including the last source of variation DMSO). Or use all data with only principal effects (time, chemical, time of exposure, and DMSO), You use then contrasts to treat specific comparisons. Further information on data would be helpful.
Dear Boulbaba,
thank you for your reply, just some explanations, i measured in fact protein level, in different organs (gills, kidney and digestive gland) of the mediterranean mussel (animal model)
I do not agree with the ANOVA or Duncan . Duncan follows the ANOVA in case of the rejection of H0. If interactions seem appropriate and or the experimental design is not complete (missing observations or unequal cell sizes, Duncan would not be suitable.
In my work, with similar experiments like yours, I use the Kruskal Wallis test of data, using the PAST program, which you can download free from the internet.
Generally, when I have data from different experiments, and the control values are different, I use the ratio, so that the control value is 100 and the data are exoressed as percentages of the controls. Thus, the graphics make the comparison immediately perceptible to the readers. The fault of this method is that I loose the standard deviation of controls.
I used Statistica -Anova but there is also the SPSS it differs in relation to the parameters
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