I tried google and the search function on this forum with no luck. I did the following experiment:

Differentiate a stem cell into four different types of cell, let's call them type A, B, C and D.

The control group usually has a 25% A, 25% B, 25% C and 25% D distribution.

The treatment group usually has 80% A, 5% B, 5% C and 10% D distribution.

However, the word "usually" is my problem. Each group (control and treatment) is done in triplicates, meaning I have 3 sets of distribution data for eatch group. The 3 sets of distribution ratio within each group are all similar to the ones shown above however they ARE different. I suppose if I carry out Chi-square analysis, assuming it is the right analysis, I need to take into account the mean and the standard deviation for both the control and the treatment group. But I just can't seem to find the right formulae. Every site I've been to gives me the following formulae:

where Oi = an observed frequency (ie count) for the ith bin

Ei = an expected (theoretical) frequency for the ith bin

Thanks in advance for your help.