I'm currently attempting to run statistical analysis on data from an experiment but have encountered an issue.
The number of participants is very low (8 in total) and there are 27 conditions after collapsing the data as much as is logically possible.
I run my stats using R statistical package and when attempting to run a Type II or Type III ANOVA the output informs me that the test:
...seems to have failed. Most commonly this is because you have too few subjects relative to the number of cells in the within-Ss design
I've got around this before by reducing the individual conditions via logical collapsing but as I stated before I've already tried that here.
While a Type I test does work I'm unhappy that there is no assumption tests.
Therefore, can any of you recommend an alternative to an ANOVA I, II, or III that might make sense to run here?
The data consists of 3 Visual Conditions x 9 Auditory Conditions totalling 27 conditions.
I hope I've provided enough information if not I'll be happy to amend.
The design is a 3x9 within-subjects/repeated measures.
The DV is Accuracy of Response.
The IVs are 3x9 visual-audio combinations.
Below is sample data for one participant (subject number 0) from the data frame AGGFRAMED.ANOVA.Collapsed.means:
subject_nr AudioAll Visual1 correct 0 1 Central Beep 1 WN Left Circle 1st 0.24 0 Left or Right Beep 1st Left Circle 1st 0.7 0 Left or Right Beep Opposite 1 WN Left Circle 1st 0.63 0 Left or Right Beep Same WN Left Circle 1st 0.63 0 No Beep Left Circle 1st 0.48 0 Post Visual Central Beep Left Circle 1st 0.42 0 Post Visual Left or Right Beep Left Circle 1st 0.6 0 Pre Visual Left or Right Beep Left Circle 1st 0.52 0 Two Beeps Same Side Left Circle 1st 0.6 0 1 Central Beep 1 WN Right Circle 1st 0.38 0 Left or Right Beep 1st Right Circle 1st 0.78 0 Left or Right Beep Opposite 1 WN Right Circle 1st 0.76 0 Left or Right Beep Same WN Right Circle 1st 0.74 0 No Beep Right Circle 1st 0.78 0 Post Visual Central Beep Right Circle 1st 0.52 0 Post Visual Left or Right Beep Right Circle 1st 0.76 0 Pre Visual Left or Right Beep Right Circle 1st 0.54 0 Two Beeps Same Side Right Circle 1st 0.7 0 1 Central Beep 1 WN SIM Circle 0.94 0 Left or Right Beep 1st SIM Circle 0.1 0 Left or Right Beep Opposite 1 WN SIM Circle 0.08 0 Left or Right Beep Same WN SIM Circle 0.39 0 No Beep SIM Circle 0.66 0 Post Visual Central Beep SIM Circle 0.9 0 Post Visual Left or Right Beep SIM Circle 0.53 0 Pre Visual Left or Right Beep SIM Circle 0.64 0 Two Beeps Same Side SIM Circle 0.46
There are 7 more subjects with the same number of conditions (27).
The code I used to run the ANOVA is as follows:
Exp9CollapsedModel <- ezANOVA(data = AGGFRAMED.ANOVA.Collapsed.means, dv = .(correct), wid = .(subject_nr), within = .(Visual1, AudioAll), type = 3, detailed = TRUE) Exp9CollapsedModel
The following is the error:
Error in lambda > 0 : invalid comparison with complex values
Error in ezANOVA_main(data = data, dv = dv, wid = wid, within = within, :
The car::Anova() function used to compute results and assumption tests seems to have failed. Most commonly this is because you have too few subjects relative to the number of cells in the within-Ss design. It is possible that trying the ANOVA again with "type=1" may yield results (but definitely no assumption tests).