The data to the right contain the quarterly sales tax receip

The data to the right contain the quarterly sales tax receipts (in thousands of dollars) submitted to the comptroller of a county for the period ending March 2011 by all 20 business establishments in that locale. Complete parts (a) through (c). a. Compute the mean, variance, and standard deviation for the population. The population mean is H (Round to two decimal places as needed.) 15.05 11.09 9.41 7.89 14.68 10.71 9.24 7.72 13.15 10.16 8.53 6.66 12.69 10.05 8.19 6.12 11.15 9.81 8.15 5.31

Solution

Getting the mean, X,          
          
u = Sum(x) / n          
Sum(x) =    195.76      
          
Thus,          
u =    9.788 [ANSWER, MEAN]
          
Setting up tables,          
x   x - X   (x - X)^2  
15.05   5.262   27.688644  
11.09   1.302   1.695204  
9.41   -0.378   0.142884  
7.89   -1.898   3.602404  
14.68   4.892   23.931664  
10.71   0.922   0.850084  
9.24   -0.548   0.300304  
7.72   -2.068   4.276624  
13.15   3.362   11.303044  
10.16   0.372   0.138384  
8.53   -1.258   1.582564  
6.66   -3.128   9.784384  
12.69   2.902   8.421604  
10.05   0.262   0.068644  
8.19   -1.598   2.553604  
6.12   -3.668   13.454224  
11.15   1.362   1.855044  
9.81   0.022   0.000484  
8.15   -1.638   2.683044  
5.31   -4.478   20.052484  
          
          
          
Thus, Sum(x - X)^2 =    134.38532      
          
Thus, as           
          
sigma^2 = Sum(x - X)^2 / N          
          
As N =    20      
          
s^2 =    6.719266 [VARIANCE]
          
Thus,          
          
s =    2.592154702 [STANDARD DEVIATION]