You've observed the following returns on bennington corporation's stock over the past five years: $15$ percent, $-15$ percent, $17$ percent, $27$ percent, and $10$ percent

a$.$ what is the arithmetic average return on the company's stock over this five$-$year period?

b$-1$ What was the variance of the company's stock returns over this period$($ do not round inyermediate calculations and round your answer to $5$ decimal places, e$.$g $\mathrm{.}32161)?$

b$-2$ What was the standard deviation of the company's stock returns over this period? $($do not round intermediate calculations and enter your answer as a percent rounded to $2$ decimal places