Dear Statalists,

I am analyzing a dataset which includes two variable "tech changing rate" and "Group". "Group" is a categorical variable from 1 to 6, which means that there are 6 groups. I am trying to see different types of groups have different rates of changing by performing statistical comparison test. My issues are:
1) Variances between the groups are not equal
2) Samples are not independent; the way I categorize groups made each group dependent.
3) Group 4 only has one observation. Group 1 has 170, Group 2 has 250, Group 3 has 700, Group 5 has 30, and Group 6 has 90.

What I have concluded so far is, I cannot use ANOVA since variance and group sizes vary. Also, since each group is not independent, I am guessing that I have to use friedman test but not sure of this. Can anyone share an idea of how I should perform statistical difference tests between theses 6 groups?

I appreciate your advice!!

Thanks!