<p>I think I understand now. If we look at example 8.1 on the previous page, the $y_{tm}$ variables may be the same, which would allow for some of the $\mathbf{z}_{tm}$ variables to be endogenous. And we pool all those endogenous variables (both the $y_{tm}$ and of the $\mathbf{z}_{tm}$) in one vector,  $\mathbf{y}_{t}$, and all the remaining ones (exogenous) in the $\mathbf{x}_{t}$ vector.</p>

CC BY-SA 3.0
2015-03-20T18:38:51.123Z
2015-03-20T18:38:51.123Z
An old man in the sea.
<p>In Hayashi's Econometrics, page 529, he states one of the assumptions we need for the FIML estimator. </p>

<p>My doubt is in the third line of point 1). He says that the vector $(y_{t1},...,y_{tM},\mathbf{z}_{t1},...,\mathbf{z}_{t1})$ are elements of $(\mathbf{y}_t,\mathbf{x}_t) $. How is that possible? If $\mathbf{y}_t=(y_{t1},...,y_{tM})'$, then it means that $\mathbf{x}_t=(\mathbf{z}_{t1},...,\mathbf{z}_{t1})$. </p>

<p>I don't think I'm understanding the 'english' here.</p>

<p>Any help would be appreciated.</p>

CC BY-SA 3.0
2015-03-20T18:35:16.270Z
In any case, I hope you have downloaded the .pdf with the various mistakes to be corrected in the book. http://fhayashi.fc2web.com/hayashi_econometrics.htm  "Known typos and errors" .pdf
Alecos Papadopoulos
CC BY-SA 3.0
2015-03-20T18:38:31.283Z
@AlecosPapadopoulos Thanks, it's not typo. I think I've got it... The notation in Hayashi is not always intuitive...
An old man in the sea.
CC BY-SA 3.0
2015-03-20T18:41:08.230Z
Indeed it is not. Get the .pdf
Alecos Papadopoulos
CC BY-SA 3.0
2015-03-20T22:15:45.860Z
@AlecosPapadopoulos Got it. ;)
An old man in the sea.
<econometrics>
A doubt on FIML assumptions
An old man in the sea.
# A doubt on FIML assumptions

(Asked by: username_0 on 2015-03-20)

In Hayashi's Econometrics, page 529, he states one of the assumptions we need for the FIML estimator.

My doubt is in the third line of point 1). He says that the vector $(y\_{t1},...,y\_{tM},\mathbf{z}\_{t1},...,\mathbf{z}\_{t1})$ are elements of $(\mathbf{y}\_t,\mathbf{x}\_t) $. How is that possible? If $\mathbf{y}\_t=(y\_{t1},...,y\_{tM})'$, then it means that $\mathbf{x}\_t=(\mathbf{z}\_{t1},...,\mathbf{z}\_{t1})$.

I don't think I'm understanding the 'english' here.

Any help would be appreciated.

**Tags:** econometrics

> **Comments:**
> **username_1**: In any case, I hope you have downloaded the .pdf with the various mistakes to be corrected in the book. http://fhayashi.fc2web.com/hayashi_econometrics.htm  "Known typos and errors" .pdf  
> **username_0**: @AlecosPapadopoulos Thanks, it's not typo. I think I've got it... The notation in Hayashi is not always intuitive...  
> **username_1**: Indeed it is not. Get the .pdf  
> **username_0**: @AlecosPapadopoulos Got it. ;)  

---

## 1 answers

### Answer by username_0 on 2015-03-20. Score: 2

I think I understand now. If we look at example 8.1 on the previous page, the $y\_{tm}$ variables may be the same, which would allow for some of the $\mathbf{z}\_{tm}$ variables to be endogenous. And we pool all those endogenous variables (both the $y\_{tm}$ and of the $\mathbf{z}\_{tm}$) in one vector, $\mathbf{y}\_{t}$, and all the remaining ones (exogenous) in the $\mathbf{x}\_{t}$ vector.


---

