In: Statistics and Probability
QUESTION 4: The returns for an asset are normally distributed. The mean return is 9.75% and the standard deviation is 3.25%. a. What is the probability of earning a negative return? (3 points) b. What is the probability of earning a return between 6.5% and 16.25%? (3 points) c What is the probability of earning a return greater than 13%? (3 points)
Random variable X : Returns for an asset
Here mean = = 9.75% = 0.0975
Standard deviation = = 3.25% = 0.0325
a) P(earning negative return) = P(X < 0)
= P(z < -3)
= 0.0013 (From statistical table of negative z values)
Probability of earning a negative return = 0.0013
b) P(6.5% < X < 16.25%) = P(0.065 < X < 0.1625)
= P(-1 < z < 2)
= P(z < 2) - P(z < -1)
= 0.9772 - 0.1587 (From statistical table of z values)
= 0.8185
Probability of earning a return between 6.5% and 16.25% is 0.8185
c) P(X > 13%) = P(X > 0.13)
= P(z > 1)
= 1 - P(z < 1)
= 1 - 0.8413 (From statistical table of z values)
= 0.1587
Probability of earning a return greater than 13% is 0.1587