Thats what I found about the pH meter:
Resolution: 0 .01 pH
Accuracy: ±0.2pH
The raw data in the first post was just an example, its random. It can be anything.
I just want to know what I have to do with the uncertainty when I calculate the average of data. So, I have 3 trials; I measure the pH: 6.53, 6.57, 6.52. Thus the average pH is 6.54. I know that the uncertainty of the raw data is 0.2 because thats the accuracy of the pH meter. What is now the uncertainty of the average 6.54?
Then I also wanted to know what happens with the uncertainty of the average if I have not just 3 trials but also, lets say, 3 different temperatures. Thus I measure the pH at different temperatures (for example).
"Table":
Temperature____pH
20...6.53....6.57....6.52....
30...
40..
When I calculate the average of all 3 trials for each temperature, doesn't the uncertainty vary for each average? Thus, for 20°C the average is 6.54, for 30°C 6.20 and for 40°C 6.00. Now I calculate the uncertainty for the first average 6.54 - doesn't it differ from that of 6.20?
Furthermore, I was actually also wondering why the uncertainty is 0.2 and the pH meter measures 2 decimal places. Thats why I asked if the I shouldn't write 0.20?
I hope its clearer now...