The US Department of Transportation reported the accompanyin

The U.S. Department of Transportation reported the accompanying data on the number of speeding-related crash fatalities during holiday periods for the years from 1994 to 2003.

(a) Compute the standard deviation for the New Year\'s Day data. (Round the answer to three decimal places.)

Solution

Getting the mean, X,          
          
X = Sum(x) / n          
Sum(x) =    1477      
As n =    10      
Thus,          
X =    147.7      
          
Setting up tables,          
x   x - X   (x - X)^2  
141   -6.7   44.89  
142   -5.7   32.49  
178   30.3   918.09  
74   -73.7   5431.69  
219   71.3   5083.69  
138   -9.7   94.09  
171   23.3   542.89  
134   -13.7   187.69  
210   62.3   3881.29  
70   -77.7   6037.29  
          
          
Thus, Sum(x - X)^2 =    22254.1      
          
Thus, as           
          
s^2 = Sum(x - X)^2 / (n - 1)          
          
As n =    10      
          
s^2 =    2472.677778      
          
Thus,          
          
s =    49.72602717   [ANSWER, STANDARD DEVIATION]