The file tax contains the quarterly sales tax receipts (in thousands of dollars) submitted to the comptroller of the village fair lake for the period of ending March 2011 by all 50 Business establishments in that locale
10.3 11.1 9.6 9.0 14.5
13.0 6.7 11.0 8.4 10.3
13.0 11.2 7.3 5.3 12.5
8.0 11.8 8.7 10.6 9.5
11.1 10.2 11.1 9.9 9.8
11.6 15.1 12.5 6.5 7.5
10.0 12.9 9.2 10.0 12.8
12.5 9.3 10.4 12.7 10.5
9.3 11.5 10.7 11.6 7.8
10.5 7.6 10.1 8.9 8.6
a. Compute the mean, variance, and standard deviation for this population.
b. What percentage of these businesses have quarterly sales tax receipts within ±1 , ±2, or ±3 standard deviations of the mean?
c. Compare your findings with what would be expected on the basis of the empirical rule. Are you surprised at the results in (b)?