These data show the ring size for a sample of 8 men 12 10 11.5,11.5, 12, 9, 9 , 11 what is the best approximation of the standard deviation of the ring size data

Given the data above N=8
mean is (12+10+11.5+11.5+12+9+9+11)/8
            thus, mean = 10.75
Sample standard, s= √(∑(x-m)²)/(n-1)
                               = 1.172 
I therefore, believe that the best approximation of standard deviation is 1.17