i have troubles answering this! please help! its for this wed march 4

i'm a first year student and our porfessor gave us this excersice. But he never explained how i will fill up those tables you see on the page. its due on March 4th. i really need some help.

sorry i meant to add finance! i just need the tables to be answered. My professor didnt explain how to get these types of information or how to do it.

WSJ Exercise Interpreting the Structure of Interest Rates a. Explaining Yield Differentials Using the most recent issue of The Wall Street Journal, review yields for the following securities: MATURITY YIELD 10-year TYPE Treasury 10-year Corporate: high-quality 10-year Corporate: medium-quality 10-year Municipal (tax-exempt) If credit (default) risk is the only reason for the yield differentials, then what is the default risk premium on the corporate high-quality bonds? On the medium-quality bonds? During a recent recession, high-quality corporate bonds offered a yield of 0.8 percent above Treasury bonds while medium-quality bonds offered a yield of about 3.1 percent above Treasury bonds. How do these yield differentials compare to the differentials today? Explain the reason for any change. Using the information in the previous table, complete the following table. In Column 2, indicate the before-tax yield necessary to achieve the existing after-tax yield of tax-exempt bonds. In Column 3, answer this question: If the tax-exempt bonds have the same risk and other features as high-quality corporate bonds, which type of bond is preferable for investors in each tax bracket? MARGINAL TAX EQUIVALENT BRACKET OF BEFORE-TAX PREFERRED INVESTORS YIELD BOND 10% 15% 20% 28% 34%