We have the formula
[tex] Cov(X,Y)=\rho_{X,Y}\sqrt{Var(X)Var(Y)} [/tex]
From the above formula,
[tex] Var(Y)=\frac{Cov(X,Y)^2}{\rho_{X,Y} ^2Var(X)}\\
Var(Y)=\frac{94.5^2}{0.9 ^215^2}\\
Var(Y)=49 [/tex]
That is variance of Y is 49 not 7.
Hence the statement is (b) False
