Please give me step by step solution to find the correct ans

Please give me step by step solution to find the correct answer. Thank you!

Heavy football players: Following arc The weights, in pounds, for offensive and defensive linemen on a professional football team at The beginning of a recent year. Find The sample standard deviation for The weights for The offensive linemen. Round The answer to one decimal place. The sample standard deviation for The weights for The offensive linemen is lb

Solution

Getting the mean, X,          
          
X = Sum(x) / n          
Sum(x) =    3507      
          
Thus,          
X =    292.25      
          
Setting up tables,          
x   x - X   (x - X)^2  
356   63.75   4064.0625  
253   -39.25   1540.5625  
351   58.75   3451.5625  
259   -33.25   1105.5625  
256   -36.25   1314.0625  
255   -37.25   1387.5625  
263   -29.25   855.5625  
331   38.75   1501.5625  
325   32.75   1072.5625  
311   18.75   351.5625  
266   -26.25   689.0625  
281   -11.25   126.5625  
          
  
          
Thus, Sum(x - X)^2 =    17460.25      
          
Thus, as           
          
s^2 = Sum(x - X)^2 / (n - 1)          
          
As n =    12      
          
s^2 =    1587.295455      
          
Thus,          
          
s =    39.84087668   [ANSWER, SAMPLE STANDARD DEVIATION]