请问答案怎么算出来是b呢
NO.PZ2015120204000021问题如下Excess stomarket returnt=a0+a1fault sprea-1+a2Term sprea-1+a3Pres party mmyt-1+etfault spreis equto the yielon Bbon minus the yielon Abon. Term spreis equto the yielon a 10-yeconstant-maturity US Treasury inx minus the yielon a 1-yeconstant-maturity US Treasury inx. Pres party mmy is equto 1 if the US Presint is a member of the mocratic Party an0 if a member of the RepublicParty.Exhibit 1.Multiple Regression OutputThe Pres party mmy variable in the mol incates ththe memonthly value for the excess stomarket return is:A.1.43 percent larger ring mocratic presincies thRepublicpresincies.B.3.17 percent larger ring mocratic presincies thRepublicpresincies.C.3.17 percent larger ring Republicpresincies thmocratic presincies.B is correct.The coefficient for the Pres party mmy variable (3.17) represents the increment in the mevalue of the pennt variable relateto the mocratic Party holng the presincy. In this case, the excess stomarket return is 3.17 percent greater in mocratic presincies thin Republicpresincies. 或者包括j截距项的其他，
NO.PZ2015120204000021 3.17 percent larger ring mocratic presincies thRepublicpresincies. 3.17 percent larger ring Republicpresincies thmocratic presincies. B is correct. The coefficient for the Pres party mmy variable (3.17) represents the increment in the mevalue of the pennt variable relateto the mocratic Party holng the presincy. In this case, the excess stomarket return is 3.17 percent greater in mocratic presincies thin Republicpresincies. 当x1=1， 不是代表fference吗
NO.PZ2015120204000021 请问a是充数的吗？ 就算算出来mkt的超额收益也应该是-1.43对吧？
问题对应条件有缺失，请更正谢谢。
老师好，这题凭着片面的条件无法求解，a3的数值是多少都没显示出来
