This should hopefully be a really simple question but I think I am confusing myself over a throwaway comment that someone made....

Say I have 20 mice undergoing two different treatments, so 10 mice in each group.

From each mouse I take two muscle biopsies, same muscle different sides (therefore 20 biopsies per treatment group).

From each biopsy I take three histological sections (therefore 60 sections per treatment group)

On each slide i count the number of fibres (ranging from 50-200 fibres per slide).

The sample size (per group) would still only be 10, as it was 10 mice that were originally treated in each group (Sample size of 20 overall)?

Can I then simply average the count per sample (so three counts per biopsy, two biopsies per sample) and compare the two groups of 10 to see whether there is a statistically significant difference beween the two groups? Or is that over-simplifying it?

Any help would be really, really appreciated.

Thanks,