Subject: Re: Hw 09
From: Benjamin Leroy <[email-masked]>
To: Brian Junker <[email-masked]>
Date: Mon, 16 Nov 2020 21:02:27 -0500

Hi Brian,

I had only solved the weighted regression for 1e, but while grading saw
everyone was just creating a big "individual" data.frame. Interestingly,
the weighted lm in R doesn't get the SE correct (a correction can be found
here:
https://www.r-bloggers.com/2015/09/linear-models-with-weighted-observations/)
- relates to the estimated degrees of freedom.

Sincerely,
Ben

On Sun, Nov 8, 2020 at 8:23 PM Brian Junker <[email-masked]> wrote:

> Thanks for the reminder Ben!
>
> #1 is a new problem.  The answers are roughly:
>
> (a) average of y1-y0 over the whole 2400 subjects (whatever numerical
> answer that is)
>
> (b) really the answer is in part (d) because we are trying to assess
> whether the x -- T connection is broken in this figure:
>
>
>
> (c) the average of y1 in the subset of the data for which T=1, minus the
> average of y0 in the subset for which T=0
>
> (d) the obvious stat 101 calculation
>
> (e) I think you can do this as a weighted regression in R.
>
> #2 should have a solution in the attached hw07 solutions from last year.
>
> #3 also has a solution in the same attached hw07 solutions.
>
> thanks!
>
> -BJ
>
> On 11/8/2020 11:21 AM, Benjamin Leroy wrote:
>
> Hi Brian,
>
> Would you mind sending me the solutions to Hw 09?
>
> Thanks
> Ben
> --
> Benjamin LeRoy
> Ph.D. Student
> Department of Statistics & Data Science
> Carnegie Mellon University
> stat.cmu.edu/~bpleroy
>
>
> --
> Brian Junker                    (412) 268 - 2718
> Department of Statistics        [email-masked]
> 232 Baker Hall                  FAX: (412) CMU-STAT
> Carnegie Mellon University        or (412) 268-7828
> Pittsburgh PA 15213 USA
>
> WWW: http://www.stat.cmu.edu/~brian/
>
>

-- 
Benjamin LeRoy
Ph.D. Student
Department of Statistics & Data Science
Carnegie Mellon University
stat.cmu.edu/~bpleroy