[R] qbinom

[peter dalgaard]

On Dec 1, 2012, at 01:00 , David Winsemius wrote:

> 
> On Nov 30, 2012, at 1:05 PM, jaybell wrote:
> 
>> sorry, I repost the question again  
> 
> Why? This was already answered.
> 
>> 
>> a=c(0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9) 
>> b=c(0.9, 0.8, 0.7, 0.6, 0.5, 0.4, 0.3, 0.2, 0.1) 
>> cor(a,b)= -1 
>> 
>> pa=qbinom(a, 1, 0.5) 
>> pb=qbinom(b, 1, 0.5) 
>> cor(pa,pb)=-0.8
>> 
>> but when  
>> pa=qbinom(a,10,0.5)
>> pb=qbinom(b,10,0.5)
>> 
>> cor(pa,pb) becomes -1 again
> 
> What part of "plot the values" was difficult to understand?

(Actually, "list the values" might be more informative in this case:

> pa
[1] 0 0 0 0 0 1 1 1 1
> pb
[1] 1 1 1 1 0 0 0 0 0

Notice that pb != 1-pa when size=1.)

-- 
Peter Dalgaard, Professor,
Center for Statistics, Copenhagen Business School
Solbjerg Plads 3, 2000 Frederiksberg, Denmark
Phone: (+45)38153501
Email: pd.mes at cbs.dk  Priv: PDalgd at gmail.com