开发者:上海品职教育科技有限公司 隐私政策详情

应用版本:4.2.11(IOS)｜3.2.5(安卓)APP下载

返回

jacqie · 2022年01月10日

为什么不是按照公式算出来加入两个变量后的R大于加入前的R就能验证需要加入两个变量？

  1. FRM I
  2. Quantitative

NO.PZ2020010801000037

问题如下：

You are interested in understanding the determinants of the yield spread of corporate bonds above a maturity matched sovereign bond. You include three explanatory variables: the leverage defined as the ratio of long-term debt to the book value of assets, a dummy variable for high yield, and a measure of the volatility of the profitability of the issuer. You are interested in testing whether there are nonlinear effects of some of these variables, and so use a RESET test including both the squared and cubic term. The R2R^2 of the original model is 68.6%, and the R2R^2 from the model that includes both additional terms is 68.9%. You have 456 observations. What do you conclude about the specification of the model?

选项：

解释：

The RESET test examines whether the two additional explanatory variables that squared and cubed fitted values have zero coefficients. It is implemented using an F-test:

(0.689−0.6862)/(1−0.689456−6) F2,450(\frac{0.689-0.686}{2})/(\frac{1-0.689}{456-6})~F_{2,450}

The F-test examines the difference between the R2R^2 in the two models. The critical value for an F2,450F_{2,450} is 3.01 (F.INV. RT(0.05,2,450) in Excel). The value of the test statistic is 2.17, which is less than the critical value, and so the null that the coefficient on the squared and cubic terms is 0 is not rejected.


我用这个公式算加入两个变量后的R是68.69%>加入前的68.53%,为什么不能这么做，而需要用假设检验？

添加评论
1 个答案

李坏_品职助教 · 2022年01月10日

嗨，从没放弃的小努力你好：


判断是否可以加入两个解释变量，不能只看R^2大小，因为算出来的新的R^2比加入前的68.53%大的那一点，必须符合统计学意义才行（必须拒绝F检验的原假设才有统计意义）。


结果发现无法拒绝H0，也就是算出来的大的这一点R^2，还不够大，不具备统计意义。

----------------------------------------------
就算太阳没有迎着我们而来，我们正在朝着它而去，加油！

  • 1

    回答

  • 0

    关注

  • 287

    浏览
相关问题

NO.PZ2020010801000037 问题如下 You are interestein unrstanng the terminants of the yielspreof corporate bon above a maturity matchesovereign bon You inclu three explanatory variables: the leverage finethe ratio of long-term to the book value of assets, a mmy variable for high yiel ana measure of the volatility of the profitability of the issuer. You are interestein testing whether there are nonlineeffects of some of these variables, anso use a RESET test inclung both the squareancubic term. The R2R^2R2 of the originmol is 68.6%, anthe R2R^2R2 from the mol thinclus both aitionterms is 68.9%. You have 456 observations. Wh you conclu about the specification of the mol? The RESET test examines whether the two aitionexplanatory variables thsquareancubefittevalues have zero coefficients. It is implementeusing F-test:(0.689−0.6862)/(1−0.689456−6) F2,450(\frac{0.689-0.686}{2})/(\frac{1-0.689}{456-6})~F_{2,450}(20.689−0.686​)/(456−61−0.689​) F2,450​The F-test examines the fferenbetween the R2R^2R2 in the two mols. The criticvalue for F2,450F_{2,450}F2,450​ is 3.01 (F.INV. RT(0.05,2,450) in Excel). The value of the test statistic is 2.17, whiis less ththe criticvalue, anso the null ththe coefficient on the squareancubic terms is 0 is not rejecte 请老师翻译一下问题，没有读懂问题，谢谢老师

2023-06-01 07:04 1 · 回答

NO.PZ2020010801000037问题如下You are interestein unrstanng the terminants of the yielspreof corporate bon above a maturity matchesovereign bon You inclu three explanatory variables: the leverage finethe ratio of long-term to the book value of assets, a mmy variable for high yiel ana measure of the volatility of the profitability of the issuer. You are interestein testing whether there are nonlineeffects of some of these variables, anso use a RESET test inclung both the squareancubic term. The R2R^2R2 of the originmol is 68.6%, anthe R2R^2R2 from the mol thinclus both aitionterms is 68.9%. You have 456 observations. Wh you conclu about the specification of the mol?The RESET test examines whether the two aitionexplanatory variables thsquareancubefittevalues have zero coefficients. It is implementeusing F-test:(0.689−0.6862)/(1−0.689456−6) F2,450(\frac{0.689-0.686}{2})/(\frac{1-0.689}{456-6})~F_{2,450}(20.689−0.686​)/(456−61−0.689​) F2,450​The F-test examines the fferenbetween the R2R^2R2 in the two mols. The criticvalue for F2,450F_{2,450}F2,450​ is 3.01 (F.INV. RT(0.05,2,450) in Excel). The value of the test statistic is 2.17, whiis less ththe criticvalue, anso the null ththe coefficient on the squareancubic terms is 0 is not rejecte这个F检验在实际考试中会怎么考，直接让计算统计量？

2023-05-20 16:22 1 · 回答

NO.PZ2020010801000037 问题如下 You are interestein unrstanng the terminants of the yielspreof corporate bon above a maturity matchesovereign bon You inclu three explanatory variables: the leverage finethe ratio of long-term to the book value of assets, a mmy variable for high yiel ana measure of the volatility of the profitability of the issuer. You are interestein testing whether there are nonlineeffects of some of these variables, anso use a RESET test inclung both the squareancubic term. The R2R^2R2 of the originmol is 68.6%, anthe R2R^2R2 from the mol thinclus both aitionterms is 68.9%. You have 456 observations. Wh you conclu about the specification of the mol? The RESET test examines whether the two aitionexplanatory variables thsquareancubefittevalues have zero coefficients. It is implementeusing F-test:(0.689−0.6862)/(1−0.689456−6) F2,450(\frac{0.689-0.686}{2})/(\frac{1-0.689}{456-6})~F_{2,450}(20.689−0.686​)/(456−61−0.689​) F2,450​The F-test examines the fferenbetween the R2R^2R2 in the two mols. The criticvalue for F2,450F_{2,450}F2,450​ is 3.01 (F.INV. RT(0.05,2,450) in Excel). The value of the test statistic is 2.17, whiis less ththe criticvalue, anso the null ththe coefficient on the squareancubic terms is 0 is not rejecte 哪里说增加了两个变量呢？只找到了原有三个变量

2023-01-08 09:27 1 · 回答

NO.PZ2020010801000037 问题如下 You are interestein unrstanng the terminants of the yielspreof corporate bon above a maturity matchesovereign bon You inclu three explanatory variables: the leverage finethe ratio of long-term to the book value of assets, a mmy variable for high yiel ana measure of the volatility of the profitability of the issuer. You are interestein testing whether there are nonlineeffects of some of these variables, anso use a RESET test inclung both the squareancubic term. The R2R^2R2 of the originmol is 68.6%, anthe R2R^2R2 from the mol thinclus both aitionterms is 68.9%. You have 456 observations. Wh you conclu about the specification of the mol? The RESET test examines whether the two aitionexplanatory variables thsquareancubefittevalues have zero coefficients. It is implementeusing F-test:(0.689−0.6862)/(1−0.689456−6) F2,450(\frac{0.689-0.686}{2})/(\frac{1-0.689}{456-6})~F_{2,450}(20.689−0.686​)/(456−61−0.689​) F2,450​The F-test examines the fferenbetween the R2R^2R2 in the two mols. The criticvalue for F2,450F_{2,450}F2,450​ is 3.01 (F.INV. RT(0.05,2,450) in Excel). The value of the test statistic is 2.17, whiis less ththe criticvalue, anso the null ththe coefficient on the squareancubic terms is 0 is not rejecte Ku我理解代表unrestrctemol，原公式中变量就是3个，为什么要加上新增的2个呢？

2022-06-25 10:30 1 · 回答

NO.PZ2020010801000037老师，请问1、这个F 2,450从何而来。？​ 2、The value of the test statistic is 2.17, whiis less ththe criticvalue, anso the null ththe coefficient on the squareancubic terms is 0 is not rejecte落在接受域，所以拒绝新加入的两个变量前的系数=0？

2022-03-31 01:15 1 · 回答