The file Tax contains the quarterly sales tax receipts (in $thousands) submitted to the comptroller of the

Question:

The file Tax contains the quarterly sales tax receipts (in $thousands) submitted to the comptroller of the Village of Fair Lake for the period ending March 2011 by all 50 business establishments in that locale:
10.311.19.69.014.513.06.711.08.410.3
8.011.27.35.312.58.011.88.710.69.5
11.110.211.19.99.811.615.112.56.57.5
10.012.99.210.012.812.59.310.412.710.5
9.311.510.711.67.810.57.610.18.98.6
a. Compute the mean, variance, and standard deviation for this population.
b. What percentage of the 50 businesses has 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)?