Rocksolid Light

News from da outaworlds

mail  files  register  groups  login

Message-ID:  

BOFH excuse #266: All of the packets are empty.


sci / sci.stat.edu / standard error=0 in stratified sampling?

SubjectAuthor
o standard error=0 in stratified sampling?george huang

1
Subject: standard error=0 in stratified sampling?
From: george huang
Newsgroups: sci.stat.edu
Date: Thu, 3 Aug 2017 13:10 UTC
X-Received: by 10.107.8.30 with SMTP id 30mr1013896ioi.129.1501765852324;
Thu, 03 Aug 2017 06:10:52 -0700 (PDT)
X-Received: by 10.31.178.139 with SMTP id b133mr6372vkf.18.1501765852232; Thu,
03 Aug 2017 06:10:52 -0700 (PDT)
Path: eternal-september.org!news.eternal-september.org!reader01.eternal-september.org!reader01.eternal-september.org!reader02.eternal-september.org!news.eternal-september.org!news.eternal-september.org!feeder.eternal-september.org!news.glorb.com!u14no179075ita.0!news-out.google.com!e5ni240qta.0!nntp.google.com!s6no274291qtc.1!postnews.google.com!glegroupsg2000goo.googlegroups.com!not-for-mail
Newsgroups: sci.stat.edu
Date: Thu, 3 Aug 2017 06:10:52 -0700 (PDT)
Complaints-To: groups-abuse@google.com
Injection-Info: glegroupsg2000goo.googlegroups.com; posting-host=2606:a000:6b5d:a301:f9b1:f00d:7d57:75dd;
posting-account=jfM62QoAAACMZRJ_r4hxeI7oNVP4ni6G
NNTP-Posting-Host: 2606:a000:6b5d:a301:f9b1:f00d:7d57:75dd
User-Agent: G2/1.0
MIME-Version: 1.0
Message-ID: <523a920f-0f76-4abb-959f-f17544a55a35@googlegroups.com>
Subject: standard error=0 in stratified sampling?
From: poboxabcde@gmail.com (george huang)
Injection-Date: Thu, 03 Aug 2017 13:10:52 +0000
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable
View all headers

Suppose I have a population with 100 events and 900 non-events. Thus, the population’s event rate is 0.1.
When I select 10% from these 100 events and also 10% from the 900 non-events, the sample’s event rate is 0.1.
If I repeat the process 20 times to create 20 samples, each sample’s rate is 0.1. Then, the standard error (the square root of the variance of these 20 means) is 0 because all the 20 event rates is 0.1.
Do I miss something or this is a legitimate stratified sampling. Please help. Thanks.

1

rocksolid light 0.9.8
clearnet tor