Firstly, thank you for responding!

When I am referring to Order, it relates to the order of two tasks within my experiment. My experiment investigated the effect of motivational state (IV-two levels)on categorisation and probabilistic reasoning. One task relates to categorisation DV and one to probabilistic reasoning.

I found an effect of experimental group on categorisation, specifically category inclusion of non-prototypic items (sum of yes responses). However, if I split my SPSS data file by Order (order 1=categorisation task first, order 2=probabilistic reasoning task first), I find that the significance only lies within order 1. The mean difference between experimental groups for order 1 split is 2.091, for order 2=2.

However, looking at order 2 data, the descriptive statistics for one experimental group look like there is a lot of variation around the mean [as reported in pervious post], such that it may be unreliable. I did look at levene's test for both order 1 and order 2 comparisons- it was significant for order 2 so I wrote down (temporarily) the equal variances not assumed inferential stats.

I also looked at box plots and interquartile range- the interquartile range for the experimental group with descriptive stats variability was 6 compared to 2's and 3's for all other plots, it also has a rather long whisker representing the top 25% upper quartile range.

I am not sure if I can interpret much from this regarding whether there is any statistical vulnerability here which I might discuss further in discussion?

What may be of interest or further confusion I don't know. If I remove split file, so analysis incorporates all data and perform a two way ANOVA with order and group being two fixed factors and categorisation as dependent variable I find no significant interaction, suggesting (I think) that the effects of group on the dependent variable are not different for order 1 compared to order 2... but as discussed above, when I split file by order and perform independent t tests looking at the effects of group on categorisation, I find that order 1 find a significant difference in categorisation score between groups and order 2 does not.

I am confusing myself, I think I am clearly misinterpreting or missing something here. Any help you can provide would be incredibly useful at this point!

Thanks again for your initial response and I look forward to hearing from you soon, I hope