6. The United States Internal Revenue Service publishes a lifetable called Table 90CM for cal culations affecting gift taxes and inheritance taxes. The table in force around 2001 has {'5 5 = 0.89658 and {'30 = 0.47084. Fit a Brass model using these two pieces of information. What are your estimates of a and [3? What value oflqo would you predict with the Brass model you have tted