Drexel dragonThe Math ForumDonate to the Math Forum



Search All of the Math Forum:

Views expressed in these public forums are not endorsed by Drexel University or The Math Forum.


Math Forum » Discussions » sci.math.* » sci.stat.math.independent

Topic: Polio, Salk vaccine
Replies: 1   Last Post: Dec 29, 2012 7:49 AM

Advanced Search

Back to Topic List Back to Topic List Jump to Tree View Jump to Tree View   Messages: [ Previous | Next ]
Luis A. Afonso

Posts: 4,528
From: LIsbon (Portugal)
Registered: 2/16/05
Polio, Salk vaccine
Posted: Dec 27, 2012 10:10 AM
  Click to see the message monospaced in plain text Plain Text   Click to reply to this topic Reply

Quoting

www.tamiu.edu/~cferguson/Ferguson PPRP.pdf - -
An Effect Size Primer: A Guide for Clinicians and Researchers Christopher J. Ferguson
Texas A&M International University

. . . Rosnow and Rosenthal (2003) discuss the effectiveness of the Salk vaccine on polio. From a treatment group (n = 200,745) receiving the Salk vaccine, 33 later had polio develop. From a control group (n = 201,229), polio developed in 115.
_______________

Let be
__X0= 115, n0=201228
__X1= 33, n1=200475
And
_____z = (x0/n0 - x1/n1)/sqrt [pp*(1-pp)*(1/n0+1/n1)]
pp=(x0+x1)/(n0+n1)
_____z= 6.71880, which gave a p-value1E-11 (z=6.70602, Abramowitz, Stegun, Handbook of Mathematical Functions).
COMMENT
If is accepted that proportions can be treated as asymptotically normal (even very away from p=0.5, which is uppermost risky) one can safely state that the vaccine is effective.
Performing a No-NHST one can state that by million of children it was expected that 571 be infected. If vaccinated at least 50.4% will not be infected (5% significance level). At late 1940´s, in Portugal, I got a full hand of high school colleagues.


Luis A. Afonso



Point your RSS reader here for a feed of the latest messages in this topic.

[Privacy Policy] [Terms of Use]

© Drexel University 1994-2014. All Rights Reserved.
The Math Forum is a research and educational enterprise of the Drexel University School of Education.