It's generally better to have a descriptive subject as you have done
here but not in your prior psoting.
You might think about how you can use this sort of result:
vec <- c(1, -1, -1, 1, 1, -1)
sample(c(-1,1),length(vec),replace=T)
Perhaps:
vec <- vec*sample(c(-1,1),length(vec),replace=T)
?sample # should explain how probabilities other than 0.5 can be
specified
On Nov 18, 2008, at 12:11 PM, Salas, Andria Kay wrote:
To clear up a question regarding my earlier posting regarding random
changes in a vector:
Say you have a vector (1, -1, -1, 1, 1, -1). I want each value in
the vector to have a probability that it will change signs when this
vector is regenerated. For example, probability = 50%. When the
vector is regenerated, the first value in the vector (1) has a 50%
chance of switching to -1. If I regenerated this vector 10 times, 5
of the times it would switch to -1.
Only "on average" would that be true. It might not switch at all if
the process is truly random.
--
David Winsemius
Similarly, I need each value in the vector to have this same
probability of switching signs when the vector is regenerated, and
each value's chances of doing so is independent of the other
values. So the second value (-1) also has a 50% chance of switching
to 1, and whether or not it does so is independent of if the first
value changes from 1 to -1 (also a 50% probability).
I hope this clears up the confusion, and I would appreciate any help
anyone can provide!
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and provide commented, minimal, self-contained, reproducible code.
