solve all the empty blue highlighted spots!

Alison is an investor who believes that past variability of stocks is a reasonably good estimate of future risk associated with the stocks. Alison work: on creating a new portfolio and has already purchased stock A. Now she considers two other stocks, B and C. Alison collected data on the historic rates of return for all three stocks, which are presented in the following table. Complete the table by calculating standard deviations for each stock