The following table lists the average annual unemployment rate for the state of Arizona from 2006 until 2016 (use formula to solve question). 

Year                 Unemployment Rate
2006..................................................4.2
2007..................................................3.8
2008..................................................6.1
2009..................................................9.9
2010................................................10.4
2011..................................................9.5

2012..................................................8.3
2013..................................................7.7
2014..................................................6.8
2015..................................................6.0
2016..................................................5.4

a. Calculate the range.

b. Calculate the variance.

c. Calculate the standard deviation.