## Introductory Statistics 9th Edition

a. Range = Highest Value - Lowest Value = 77-35 = 42 $Variance = σ^2=(∑〖(x-μ)〗^2 )/n-1$ $=[∑(x^2) -∑(x)^2]/N/n-1$ $=[64871-(1113^{2}/20)/19]$ $=(64871-61938.45)/19$ $=154.3447$ Standard Deviation = $\sqrt 154.3447 = 12.4326$ b. Coefficient of Variation=$12.4326\div55.65\times100% =22.32%$ c. The values are sample statistics, because the data collected are 20 randomly selected workers among all the workers.