The coefficient of correlation between X and Y is 0.6, their covariance is 4.8. The variance of X is 9. Then the standard deviation of Y is:

Correct option is A

The formula for the coefficient of correlation (r) is:

Where:
· r=0.6r = 0.6r=0.6 (correlation coefficient)
· Cov (X, Y)= 4.8 (covariance of X and Y)
· σ2​X = 9 (variance of X)
· σX​= 9 ​= 3 (standard deviation of X)
· σY​ is the unknown (standard deviation of Y)
Rearrange the formula to solve for σY:

Correct Answer: