Re: [R] Probability Question

2011-12-28 Thread peter dalgaard

On Dec 28, 2011, at 05:11 , Matilda E. Gogos wrote:

 Hello,
 
 This is a question from a class I'm not in (it's also winter break). But,
 all the same, I don't know where to start in R with this. It's supposed to
 be done in R.  So, can anyone direct me with a helpful hint or 2, on how to
 get started with the question listed below, or tell me how I can re-post
 this to Usenet groups sci.stat.consult., so they can help with this
 question:

We're not supposed to help with homework here, and neither is sci.stat.consult. 
However, since it is Christmas... 

This looks like a pen-and-paper (theory) exercise, not an R one. Are you sure 
that the R requirement is not intended to apply to exercises further down the 
list?  You might use expand.grid() to find the elements of the powerset, but 
I'm not sure that actually helps understanding.

 
 Exercise 1. Let Ω = {H,T,E}(a set with 3 elements, called H ,T and E . You
 can think of “heads”, “tails” and “edge” if you like, but this
 interpretation is not necessary).
 
 1. List the elements of the powerset P (Ω) of Ω. (Recall that the powerset
 of a set is the set of all subsets of that set, including Ø (the empty set)
 and the whole set.)
 
 2. Suppose P is a set function on Ω (that is, a rule assigning real numbers
 to subsets of Ω). Suppose that
 
 P({H,T}) = 3, P({H,E}) = 3, P({H}) = 1 444
 
 Why is it impossible that P is a probability measure ? (That is, no matter
 how P is defined on the remaining subsets of Ω, it can’t be a probability
 measure.)
 -- 
 Best,
 Matilda Gogos
 matildaelizabe...@gmail.com
 
   [[alternative HTML version deleted]]
 
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-- 
Peter Dalgaard, Professor,
Center for Statistics, Copenhagen Business School
Solbjerg Plads 3, 2000 Frederiksberg, Denmark
Phone: (+45)38153501
Email: pd@cbs.dk  Priv: pda...@gmail.com

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Re: [R] Probability Question

2011-12-28 Thread David Winsemius


On Dec 28, 2011, at 3:15 AM, peter dalgaard wrote:



On Dec 28, 2011, at 05:11 , Matilda E. Gogos wrote:


Hello,

This is a question from a class I'm not in (it's also winter  
break). But,
all the same, I don't know where to start in R with this. It's  
supposed to
be done in R.  So, can anyone direct me with a helpful hint or 2,  
on how to
get started with the question listed below, or tell me how I can re- 
post

this to Usenet groups sci.stat.consult., so they can help with this
question:


We're not supposed to help with homework here, and neither is  
sci.stat.consult. However, since it is Christmas...


This looks like a pen-and-paper (theory) exercise, not an R one. Are  
you sure that the R requirement is not intended to apply to  
exercises further down the list?  You might use expand.grid() to  
find the elements of the powerset, but I'm not sure that actually  
helps understanding.




Exercise 1. Let Ω = {H,T,E}(a set with 3 elements, called H ,T and  
E . You
can think of “heads”, “tails” and “edge” if you like,  
but this

interpretation is not necessary).

1. List the elements of the powerset P (Ω) of Ω. (Recall that the  
powerset
of a set is the set of all subsets of that set, including Ø (the  
empty set)

and the whole set.)


I don't think I'm violating the no homework rule too much by pointing  
our that there is a powerset()  function in the sets package. Why one  
wouldn't do this one in their head is a bit beyond me,  but if it's  
really true that these need to be done in R, then maybe the author's  
intent ti to get that package installed and loaded?




2. Suppose P is a set function on Ω (that is, a rule assigning real  
numbers

to subsets of Ω). Suppose that

P({H,T}) = 3, P({H,E}) = 3, P({H}) = 1 444

Why is it impossible that P is a probability measure ? (That is, no  
matter
how P is defined on the remaining subsets of Ω, it can’t be a  
probability

measure.)
--
Best,
Matilda Gogos
matildaelizabe...@gmail.com



David Winsemius, MD
West Hartford, CT

__
R-help@r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.


[R] Probability Question

2011-12-27 Thread Matilda E. Gogos
Hello,

This is a question from a class I'm not in (it's also winter break). But,
all the same, I don't know where to start in R with this. It's supposed to
be done in R.  So, can anyone direct me with a helpful hint or 2, on how to
get started with the question listed below, or tell me how I can re-post
this to Usenet groups sci.stat.consult., so they can help with this
question:

Exercise 1. Let Ω = {H,T,E}(a set with 3 elements, called H ,T and E . You
can think of “heads”, “tails” and “edge” if you like, but this
interpretation is not necessary).

1. List the elements of the powerset P (Ω) of Ω. (Recall that the powerset
of a set is the set of all subsets of that set, including Ø (the empty set)
and the whole set.)

2. Suppose P is a set function on Ω (that is, a rule assigning real numbers
to subsets of Ω). Suppose that

P({H,T}) = 3, P({H,E}) = 3, P({H}) = 1 444

Why is it impossible that P is a probability measure ? (That is, no matter
how P is defined on the remaining subsets of Ω, it can’t be a probability
measure.)
-- 
Best,
Matilda Gogos
matildaelizabe...@gmail.com

[[alternative HTML version deleted]]

__
R-help@r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.