Is it valid (reliable etc.) to compare a small sample with a large sample (which is made up of several small samples) when both samples are from the same population?
There are 3 firms. Each firm specialises in the manufacture of a particular product, hence it is classified in that way.
Firm A manufactures common cold medicines, Firm B manufactures arthritis medicines and Firm C manufactures heartburn medicines.
The common element linking the three firms is that they are all medicine manufacturers.
Now, Firm A and C only produce generic medicines and Firm B only produces branded medicines.
I have a sample of 80 workers from each firm and I want to test how satisfied they are in regard to their work-life balance. I am using correlation analysis etc.
I am comparing Firm A with B and C but I also want to compare Firm A and C with B. (Firm A and C are grouped together because they are generic medicine providers).
Is comparing a sample of 80 peoples (Firm B) with a sample of 160 people (Firm A and C) any reason for statistical concern?