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410140980 · 2021年09月06日

whether stock and bond market returns explain the returns of a portfolio of utility shares run by the firm.不是应该用probit或者logit模型吗?

NO.PZ2015120204000026

问题如下:

An analyst is addressing the following research topics: how investment fund characteristics affect fund total returns and whether stock and bond market returns explain the returns of a portfolio of utility shares run by the firm.

To explore the first topic, he uses the average annualized rate of return(in percent) of 555 large-cap US equity funds over the past five years. The independent variables are fund expense ratio, portfolio turnover, the natural logarithm of fund size, fund age, and three dummy variables.For the second topic, he establish whether bond market returns (proxied by returns of long-term US Treasuries) and stock market returns(proxied by returns of the S&P 500 Index) explain the returns of a portfolio of utility stocks being recommended to clients.

Whether he should have estimated the models using a probit or logit model instead of using a traditional regression analysis?

选项:

A.

Both should be estimated with probit or logit models.

B.

Neither should be estimated with probit or logit models.

C.

Only the first analysis should be done with probit or logit models.

解释:

Probit and logit models are used for models with qualitative dependent variables, such as models in which the dependent variable can have one of two discrete outcomes (i.e., 0 or 1). The analysis in the two exhibits are explaining security returns, which are continuous (not 0 or 1)variables.

老师这题里面的这句话是否股票或者债券会影响这家公司投资公共事业的回报率。

结果不就只有两种,是或者否吗?

因为在我理解看来 whether 的问题,回答只有yes or no。所以麻烦解释一下这个第二个研究问题为什么不用着两种模型

1 个答案

星星_品职助教 · 2021年09月08日

同学你好,

看一下“whether”这句话的描述:“ whether bond market returns (proxied by returns of long-term US Treasuries) and stock market returns(proxied by returns of the S&P 500 Index) explain the returns of a portfolio of utility stocks......”

可以看出,最后的Y变量是一个return,而不是“是/否”。基于return是一个连续变量,这是不能用probit/logit模型的根本原因。

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如果这个“whether”的问题回答是yes,那说明的是这个方程是成立的,意为最后那个“return”可以被前两个return所解释。而不去说明Y变量本身是二值变量。

同理,如果回答是no,说明的是方程是不成立的,即这三个return之间没有线性关系,也同样不能说明Y值本身是什么变量。