Returns for the Corrigan Company over the last 3 years are shown below. What's the standard deviation of Corrigan's returns? (Hint: this is a sample, not a complete population) Year 2005 2004 2003 Return 25% -12 30 a) 25.18% b) 21.79% c) 22.94% d) 27.54% e) 20.10%