Answer the following questions.

1. Calculate the duration of a four-year, 10 percent annual coupon bond with a required rate of return of 10%. (Par value of the bond is $1,000.)
2. Calculate the duration of a four-year, 10 percent annual coupon bond with a required rate of return of 12%. (Par value of the bond is $1,000.)
3. Calculate the duration of a four-year, 10 percent annual coupon bond with a required rate of return of 14%. (Par value of the bond is $1,000.)
4. From (1), (2), and (3), what can you conclude about the relationship between duration and yield to maturity?