Suppose that the market portfolio is equally likely to increase by 24% or decrease by 8%.

Suppose that the market portfolio is equally likely to increase by​ 24% or decrease by​ 8%. Security​ "X" goes up on average by​ 29% when the market goes up and goes down by​ 11% when the market goes down. Security​ "Y" goes down on average by​ 16% when the market goes up and goes up by​ 16% when the market goes down. Security​ "Z" goes up on average by​ 4% when the market goes up and goes up by​ 4% when the market goes down.