Is the mean of means the best option for my data?

#1
Ten subjects have been tested by the same measure (imagine an intelligence test). But, there is different number of taking part in experiment for each subject (e.g., Subject A: 1 times; Subject B: 7 times; Subject C: 2 times; etc.). Is the mean of means the best option for calculating the mean scores? If yes then how I should calculate its SD? Could you please introduce a tutorial?


Thanks.
 
#3
Thanks, but it does not seem related to my question. I am looking for the best method for calculating the mean, and then its SD formula.