I am new here (and also to statistics ).

I have a data set of many measurements. For each one of them I calculated the mean and the SD (deviation). From that I calculated separately for each of the data set a SEM.

Now I would like to multiply, divide add and subtract this data samples from/with each other.

Doing so for the actual values is quite trivial, but what do I do with the SEM-values.

How do this SEM Values changed according the applied calculation?

Example( with data from the internet):

set 1: 46,42,44,45,43 => mean 44 ; SD= 1.6 ==> SEM : 1.6

set 2: 52,80,22,30,36 => mean 44 ; SD = 22.9 ==> SEM : 10.3

What do I do with the two sets if I want to combine them together?

I would appreciate any help I can get.

Thanks

Assa