We do really want you to finish the homework. If you've got more
questions, please send them to the list. This should not take anything
like 30 hours.
I hope you all enjoyed thanksgiving..
Gary
Phillip Y. Lipscy writes:
> Hi Dave,
>
> I think it's less of a conceptual problem than raw grinding.
I know. Part of me feels guilty for working everyone so hard. But most of me,
especially the ex-Marine part, feels that taking it easy on you does not make you
better off.
Think of it using the Rubin Causal Model! ;-) The units are the students. The
outcome is something you care about (which could range from being able to do
publishable research, to getting a Ph.D in less than 7 years, to getting an
offer for a tenure track academic appointment). The treatments are various
options for this class (ranging from the big picture of I-teach-it versus
I-don't-teach it, to smaller issues of take home exams versus in class exams,
to the minutia of whether or not 1(c) is removed from problem set 7).
My goal is to select treatment options that have a positive causal effect on
the outcomes that you care about. Of course, some treatments (drop 1(c)) are
too small to have an measurable impact on some outcomes (get a job offer). But
the direction is the main thing that I am trying to get correct.
It should be obvious, but I can't help to mention that, if there were other
outcomes that I cared more about (making Gary's life easier, minimizing
complaints about me to the department chair), I would make very different
treatment selections.
Given that (to the extent that you believe that data for other political
science programs applies to Harvard and that the past predicts the future),
only around 1/2 of you would be likely to get that academic job offer within
the next 7 years if we select the "standard" treatment options, I feel strongly
that the "standard" treatment could be signficantly improved.
Of course, there is a point at which grinding you too hard could make the
treatment effect negative, but I like to think that our new friendly (almost no
readings!) GOV 1000 is far from that point.
> well, my point being, spending i.e. 10 hrs on 1c would probably not be a good
> idea if you decide to later throw it out :)
Point well taken. To the extent that we throw problems out (and, to be honest,
I am not sure how much fight is left in me), the questions most likely to go
are:
1(b, c, f); 4; 6.
So, feel free to optimize your work accordingly.
> My approach then will be to skip all of the time-consuming subparts of each
> question for now and return to them later, but try to take a stab at each problem.
>
> Does that make sense?
I would skip the above questions as a first pass.
As always, I appreciate your (and everyone's) comments and feedback.
Dave
> -Phillip.
>
>
>
> -------------------------------------------------
> Phillip Y. Lipscy
> Perkins Hall Room #129
> 35 Oxford Street
> Cambridge, MA 02138
> (617)493-4893
> lipscy(a)fas.harvard.edu
>
> Ph.D. Candidate
> Harvard University, FAS, Department of Government
> -------------------------------------------------
>
>
>
>
>
>
--
David Kane
Lecturer In Government
617-563-0122
dkane(a)latte.harvard.edu
Please avoid sending me Word or PowerPoint attachments.
See http://www.fsf.org/philosophy/no-word-attachments.html
Dear Dave,
My current estimate is that this problem set will easily exceed 30 hrs of work.
Given that, are there specific parts of the problem set that we should leave to
the end (i.e. the matching exercise), just so we do not spend too much time on
substantively less important parts of the material?
Thanks,
Phillip.
-------------------------------------------------
Phillip Y. Lipscy
Perkins Hall Room #129
35 Oxford Street
Cambridge, MA 02138
(617)493-4893
lipscy(a)fas.harvard.edu
Ph.D. Candidate
Harvard University, FAS, Department of Government
-------------------------------------------------
Questions like this should go to the list. I am afraid that people are getting
jealous of the fact that I get to answer almost every question first! ;-)
In general, you don't delete, you just subset out what you want and then
reassign. That is, x is what it is. To get x without something you need to
reassign its value. (The one exception is the use of NULL for column names.) In
general, the two ways of doing this are subset by numbers and by names. Here
are some examples:
> x <- data.frame(year = 1988:1994, vote = 17:11, other = letters[1:7])
> x[-3, ] # drops the third row
year vote other
1 1988 17 a
2 1989 16 b
4 1991 14 d
5 1992 13 e
6 1993 12 f
7 1994 11 g
> x # but x is unaffected
year vote other
1 1988 17 a
2 1989 16 b
3 1990 15 c
4 1991 14 d
5 1992 13 e
6 1993 12 f
7 1994 11 g
> x <- x[-3, ] # permanently changes x
> x
year vote other
1 1988 17 a
2 1989 16 b
4 1991 14 d
5 1992 13 e
6 1993 12 f
7 1994 11 g
> x[, -2] # drops the second column
year other
1 1988 a
2 1989 b
4 1991 d
5 1992 e
6 1993 f
7 1994 g
> x$other <- NULL #permanently deletes other
> x
year vote
1 1988 17
2 1989 16
4 1991 14
5 1992 13
6 1993 12
7 1994 11
>
Dave
Traci Burch writes:
> Dave, for future reference, how do you delete variables from a data frame? Do you have to use that dataframe editor thing each time or is there a code that's the opposite of cbind or rbind? or do you have to make a new data frame with just the rows and columns that you want?
>
> T
> <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
> <HTML><HEAD>
> <META http-equiv=Content-Type content="text/html; charset=iso-8859-1">
> <META content="MSHTML 6.00.2719.2200" name=GENERATOR>
> <STYLE></STYLE>
> </HEAD>
> <BODY bgColor=#ffffff>
> <DIV><FONT face=Arial size=2>Dave, for future reference, how do you delete
> variables from a data frame? Do you have to use that dataframe editor
> thing each time or is there a code that's the opposite of cbind or rbind?
> or do you have to make a new data frame with just the rows and columns that you
> want?</FONT></DIV>
> <DIV><FONT face=Arial size=2></FONT> </DIV>
> <DIV><FONT face=Arial size=2>T</FONT></DIV></BODY></HTML>
--
David Kane
Lecturer In Government
617-563-0122
dkane(a)latte.harvard.edu
Please avoid sending me Word or PowerPoint attachments.
See http://www.fsf.org/philosophy/no-word-attachments.html
if anyone has any comments or suggestions on the lectures or other aspects
of the class, I'd appreciate hearing from you.
Thanks,
Gary
p.s. I'm planning to continue where I left off on Monday next week, so
please bring the xeroxes we gave you yesterday.
: Gary King, King(a)Harvard.Edu http://GKing.Harvard.Edu :
: Center for Basic Research Direct (617) 495-2027 :
: in the Social Sciences Assistant (617) 495-9271 :
: 34 Kirkland Street, Rm. 2 HU-MIT DC (617) 495-4734 :
: Harvard U, Cambridge, MA 02138 eFax (928) 832-7022 :
Good question for the list.
Hmmm.
By deduction, there must be something different about the two
directories. You can read about the messy details about how R starts
up here:
> help(.Rprofile)
My best guess is that you have a messed up .Rdata file (or .Rprofile)
in your ~/fall02/gov1000 directory. Look for them (or anything else
weird) with ls -a. Delete them if you find them. Then try
restarting. That should work.
Dave
Ryan Thomas Moore writes:
> Dave:
>
> I restarted R, and within my ~/fall02/gov1000 directory, I still don't
> have the ctest package. But, if I start R in my home (/rmoore) directory,
> the package:ctest does appear. I'd rather use R in the ~/fall02/gov1000
> directory if I can, but if not, I'm ok with using it in the home
> directory. In short, I have a viable solution, but is there any way I can
> get the package:ctest to appear in the /gov1000 directory I've created?
>
> Thanks!
> Ryan
>
> ------------------------------------------
> Ryan T. Moore ~ Government & Social Policy
> Ph.D. Candidate ~ Harvard University
>
>
--
David Kane
Lecturer in Government
617-563-0122
dkane(a)latte.harvard.edu
I am desperately trying to write the following two equations. Can anyone
assist me?
1) psi= w^(I) - w^(0), and
2) E(V_2) = B_0 + B_1*V_1 + B_2*P_2 + psi*I_2
thanks
yongwook
-----------------------------
Yongwook Ryu
PhD Candidate
Department of Government
Harvard University
Tel:617-493-3397
Email: yryu(a)fas.harvard.edu
-----------------------------
can some kind person be kind enough to tell me how I can transfer a file from
my home directory to another directory?
yongwook
-----------------------------
Yongwook Ryu
PhD Candidate
Department of Government
Harvard University
Tel:617-493-3397
Email: yryu(a)fas.harvard.edu
-----------------------------
does anyone know how to write italics in latex?
yongwook
-----------------------------
Yongwook Ryu
PhD Candidate
Department of Government
Harvard University
Tel:617-493-3397
Email: yryu(a)fas.harvard.edu
-----------------------------
