a$-1.$ What would have been the average value of your gross monthly payouts on the puts over the $10-$year period October $1977$September $1987?($Do not round intermediate calculations. Round your answer to $4$ decimal places.$)$ a$-2.$ The standard deviation? $($Do not round intermediate calculations. Round your answer to $4$ decimal places.$)$b$-1.$ What would have been the average value of your gross monthly payouts on the puts if you extend the sample by one month to include October $1987?($Do not round intermediate calculations. Round your answer to $4$ decimal places.$)$b$-2.$ The standard deviation? $($Do not round intermediate calculations. Round your answer to $4$ decimal places.$)$