What is the standard deviation of the data set {2,1,1,2,2,3}?

0.687

Step-by-step explanation:

step 1:  find mean of 6 data values (should be 11/6)

step 2:  find the difference of the mean and each of the six data values

step 3: square each of those six differences

step 4:  find the mean of the squared values (should be 102/216)

step 5:  take the square root of 102/216

the distance between point a and point b is 6 units