Here are the percentage returns on two stocks.

a$-1.$ Calculate the monthly variance and standard deviation of each stock. $($Do not round intermediate calculations. Round your

answers to $1$ decimal places.$)$

a$-2.$ Which stock is the riskier if held on its own?

Digital Cheese

Executive Fruit

b$.$ Now calculate the variance and standard deviation of the returns on a portfolio that invests an equal amount each month in the two

stocks. $($Do not round intermediate calculations. Round your answers to $1$ decimal places.$)$Here are the percentage returns on two stocks. Month Digital Cheese Executive Fruit January $15\%7\%$ February $-31$ March $54$ April $713$ May $-42$ June $35$ July $-2-3$ August $-8-2$ a$-1.$ Calculate the monthly variance and standard deviation of each stock. $($Do not round intermediate calculations. Round your answer to $1$ decimal place.$)$ a$-2.$ Which stock is the riskier if held on its own? Digital Cheese Executive Fruit b$.$ Now calculate the variance and standard deviation of the returns on a portfolio that invests an equal amount each month in the two stocks. $($Do not round intermediate calculations. Round your answer to $1$ decimal place.$)$ Problem $7-12$ Diversification Here are the percentage returns on two stocks. a$-1.$ Calculate the monthly variance and standard deviation of each stock. $($Do not round intermediate calculations. Round your answer to $1$ decimal place.$)$ a$-2.$ Which stock is the riskier if held on its own? Digital Cheese Executive Fruit b$.$ Now calculate the variance and standard deviation of the returns on a portfolio that invests an equal amount each month in the two stocks. $($Do not round intermediate calculations. Round your answer to $1$ decimal place.$)$