Why incorrect sampling with weighted randsample?

10 visualizzazioni (ultimi 30 giorni)
Depending on the distribution of the weights w used in randsample(population,k,true,w), the random sampling seems to be incorrect. For example, this problem arises if the weights are as weight2 below, but works correct with weight1:
%% --------------------------------------------------------- %%
values = [-5:5];
weight1 = [0.02 0.03 0.05 0.1 0.0 0.2 0.2 0.1 0.05 0.03 0.02];
weight2 = [0.02 0.00 0.05 0.1 0.35 0.28 0.2 0.0 0.00 0.00 0.00];
n = 1000000;
sample1 = randsample(values,n,true,weight1);
sample2 = randsample(values,n,true,weight2);
%% --------------------------------------------------------- %%
Has anyone else experienced this problem? Is there a workaround?
Best regards Kristin

Risposta accettata

the cyclist
the cyclist il 21 Feb 2014
Can you please explain the evidence that makes you say that "the random sampling seems to be incorrect"?
When I run the commands
figure
hist(sample1,values)
figure
hist(sample2,values)
the results look as I would expect.
  2 Commenti
Kristin
Kristin il 21 Feb 2014
I'm so sorry, I made a simple mistake in plotting the distributions. Your reply helped me to see my mistake!
Thanks for taking your time!
/Kristin
the cyclist
the cyclist il 21 Feb 2014
The best form of thanks is the acceptance of an answer. :-)

Accedi per commentare.

Più risposte (0)

Tag

Non è stata ancora inserito alcun tag.

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by