Hi, Comunnity!
I got here a question regarding entering the data for one way ANOVA in GraphPad 7.
In short:
Measured variable - cytokine (concentration in plasma).
3 groups of samples/conditions.
2 measurements per sample (duplets).
Comparisons done for 12 cytokines.
N samples per group: 3, 5, 6.
Decision: to analyse each cytokine independently using one way ANOVA mode with modification for non-parametric, Kruskall-Wallis test with Dunn's correction for multiple comparisons.
The problem is how to enter data. there are 2 options.
1. To enter pre-calculated mean of two meausrments per sample. (1 row, 3 columns);
2. To enter directly values of both measurments (2 rows - representing measurement 1 and 2; 3 columns - representing conditions), assuming that one way ANOVA mode anyways analyses mean of rows and between columns.
Second option gives better p-values, but I suspect it is due to the different ranking order for each sample, and that in second case software actually sees measurments per sample as independ samples doubling the N. Is it right?..
What would be the correct decision in this situation?
Thank you!
Dear Valery,
What I think is that using the second opcion, your are taking into account the both measurements per sample (technical replicates) as an independent N (biological replicates). So the software is increasing the N samples and because of that, as you said, the p-values are better.
In your first opcion, for a selected citokine, would this be your design?
Table format: Grouped
Row: Cytokine X
Column
Group A : Condition 1, 3-6 subcolumns (for each N)
Group B : Condition 2, 3-6 subcolumns (for each N)
Group C : Condition 3, 3-6 subcolumns (for each N)
Have I unerstood correctly??
Erica
Dear you can analyse your data with ANOVA but comparing the data in 2 groups you can use student t-test.
Dear you can analyse your data with ANOVA but comparing the data in 2 groups you can use student t-test.
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