Hi,

I'm new to the site and would be greatly appreciative if someone could help me out with the following problem.

I have 20 results from two repeat experiments (10 data values per experiment). I calculate the mean and sem for each data set (i.e. for each set of 10 results) using the "=average(A1:A10)" (for mean) and "=stdev(A1:A10)/sqrt(count(A1:A10))" (for sem) formulae in Excel.

Because the second experiment is an identical repeat of the first experiment, I want to combine the results. However, I do not know how to combine the two mean values and the two sem values I calculated in Excel.

Can someone advise on how to perform this correctly? I have tried to read around and, unfortunately, have been confused by terms like "xbar" etc!

I have listed some data below and would be very grateful if this could be used in any responses to illustrate the correct calculation. Thank you in advance.

Experiment 1:

Result 1 = 3
Result 2 = 4
Result 3 = 5
Result 4 = 3
Result 5 = 2
Result 6 = 6
Result 7 = 3
Result 8 = 4
Result 9 = 6
Result 10 = 5

Mean = 4.1
sem = 0.43

Experiment 2:

Result 1 = 4
Result 2 = 5
Result 3 = 3
Result 4 = 1
Result 5 = 6
Result 6 = 4
Result 7 = 3
Result 8 = 3
Result 9 = 3
Result 10 = 4

Mean = 3.6
sem = 0.43

How do I now calculate a single mean and sem value for all 20 results? Thanks.