Add them.

   X                                         
   4                                      
   2                                      
   2                                      
   3                                      
   5
   6
 ---
  22

Out beside that column square every number, that is, multiply
it by itself, then add that column and you have:

     X      X²                                         
     4      16                                   
     2       4                                  
     2       4                                  
     3       9                                  
     5      25
     6      36 
   ---     --- 
 ∑x=22  ∑x²=94

The variance is s².  The short-cut formula is:
   
     n(∑X²) − (∑X)²
s² = --------------
       n(n − 1)

We substitute  ∑x=22,  ∑x²=94, and n=6 (the number of numbers)

     6(94) − (22)²
s² = -------------- 
       6(6 − 1)

      564 − 484
s² = -------------- 
         6(5)

          80
s² = -------------- 
          30

s² =  = 2.66666666667

That's the variance.

To get the standard deviation, take the square root:

s =  =  = 1.632993162

Round off all answers to the nearest hundredth.

s² = 2.67

 s = 1.63

Edwin