I have 30 participants. They have a pre score and a post score. I am testing whether this changes. There are five observations per participant.
When the data are analyzed using a t-test there is a significant difference. When analyzed using linear mixed effects (i.e., with random subject and item intercepts) there is no significant difference (using the lmerTest package in R to generate p values via Satterthwaite's degrees of freedom method).
What conclusions can I draw from the difference between results?