I have a set of data and I am going to apply the lme mixed model. However, the data are not normally distributed (see the graph below).
I tried (log, sqrt, zscore) and box-cox transformations and even the graphs look better, Kolmogorov-Smirnov test gave me a max p-value=0.008.
The residual plot for the lme model (used data were transformed with box-cox) is attached below and
To my knowledge, the residuals plot should not have any pattern and I can not see any on my plot, but why the normality tests (Kolmogorov-Smirnov / Shapiro) gave me values <0.05?
My question is:
What also can I do to normalize my data and use them for mixed model (lme)?