$12-9$ Calculating Returns and Variability $($LO$1)5$pointseBookReferencesYou've observed the following returns on Regina Computer's stock over the past five years: $10\%,-11\%,18\%,19\%,$ and $10\%.$a$.$ What was the arithmetic average return on Regina's stock over this five$-$year period? $($Round the final answer to $1$ decimal place.$)$Average return$\%$b$-1.$ What was the variance of Regina's returns over this period? $($Do not round intermediate calculations. Round the final answer to $5$ decimal places.$)$Varianceb$-2.$ What was the standard deviation of Regina's returns over this period? $($Do not round intermediate calculations. Round the final answer to $1$ decimal place.$)$Standard deviation$\%$