A random variable x is normally distributed with a mean of 10 and a

1. A random variable X is normally distributed with a mean of 10 and a standard deviation of 3.
(a) Find P(X > 12)
(b) Find P(X ≤ 5)
(c) Find P(12 ≤ X < 20)
(d) Find b such that P(X > b) = 0.9782
2. A random variable X is normally distributed with a mean of 95 and a standard deviation of 12. If
P(A < X < B) = 0.8592, find A and B such that A and B are symmetric about the mean.
3. The weights of a particular species of animal are normally distributed with a mean of 10 pounds and a standard
deviation of 2 pounds. If a newborn animal of this species is in the 85th percentile, what is its weight?
4. How many days will it take for a sum of $500 to earn $85 interest if it is deposited into an account paying simple
interest at the rate of 4% per year?
5. An account pays simple interest at an annual rate of 4.75%. If the account grows to $15,250 over a 9 month
period, what was the original amount placed in the account?
6. The amount of money in an account paying interest that is compounded quarterly doubles over a twenty year
period. What is the annual interest rate?
7. How long will it take for $490 to grow to $900 if it is placed in an account that pays interest at 4.75%/year
compounded monthly?
8. An account pays interest at 5.75%/year compounded continuously. How much will be in the account at the end
of the period if $925 is invested for a 15 year period?
9. What is the effective rate of interest of an account that pays 5.75% per year compounded daily?
10. What is the effective rate of interest of an account if it pays interest compounded quarterly and $5,000 grows to
$7,500 over a 9 year period?