You have observed the following return on CB Computer$$s stock over the past $6$ years: $8\%,-12\%,$

$12\%,38\%,5\%$ and $14\%.(7$ Marks$)$

a$.$ What was the arithmetic average return on CB Computer$$s stock over the $6-$year period?

b$.$ What was variance of CB Computer$$s returns over this period? The standard deviation