I was wondering if anyone could shed some light on a current situation I have encountered. I have a study set-up with 13 participants that I am examining over 5 time-points, hence, I intend to conduct a one-way ANOVA. However, on one of the time-points, a participant was unable to attend the situation so I now have a missing case but given there only being 13 participants I am reluctant to remove the participant from the data set. Could anyone please advise what to do in this situation? My data is laid out in wide-format e.g. every row is a participant and each measure has 5 columns such as strengthday1, strengthday2 etc.

Thank you in advance,

Brett