I would like to compare a continuous variable across 5 health status groups, but one of the groups has only 1 observation. Would an ANOVA/Kruskal-Wallis be valid? What can I do about the group with only 1 observation?
The group sizes are:
A: 12 B: 8 C: 9 D: 7 E: 1
Background info: I work in biostatistics and my datasets are fairly small, and some outcomes are rare in biology. Collecting samples is also dependent on patients and is an expensive procedure, so getting a larger sample is not a feasible solution.
Edit: What I currently do is to omit the group with only one observation in my analysis, however I am not sure about the validity of that.