I have a variable VA and want to know if there are significant differences in this variable between group A and group B.

N = 93 samples

Situation 1:

In Group A the n = 53 in Group B n = 40 (these groups were defined considering that the group A have the treatment X and the group B don’t have the treatment DX).

Situation 2:

In Group A the n = 76 in Group B n = 17 (these groups were defined considering that the group A was submitted to surgery S and the group B don’t was submitted to surgery DS).

N = 17 samples (subgroups of situation 2)

Situation 3:

In Group C the n = 11 in Group D n = 6 (these groups were defined considering that the group C is (X + S) and the group D (DX + S).

Situation 4:

In Group C the n = 42 in Group D n = 34 (these groups were defined considering that the group C is (X + DS) and the group D (DX + DS).

Questions?

- How to verify that the number of individuals is sufficient to verify the statistical significance?

- Is it possible to justify that these are solid, that is, allowing a sound statistical interpretation / reasonable despite the n presented?

I cannot change the n because the samples are difficult to obtain and very time consuming. Furthermore many of the studies present an overall sample less than 93.

best regards