The Math Forum

Search All of the Math Forum:

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

Math Forum » Discussions » Courses » ap-stat

Notice: We are no longer accepting new posts, but the forums will continue to be readable.

Topic: Confidence interval for p
Replies: 4   Last Post: Apr 10, 1997 9:41 AM

Advanced Search

Back to Topic List Back to Topic List Jump to Tree View Jump to Tree View   Messages: [ Previous | Next ]

Posts: 119
Registered: 12/6/04
Confidence interval for p
Posted: Apr 9, 1997 6:16 PM
  Click to see the message monospaced in plain text Plain Text   Click to reply to this topic Reply

Yet another thought on using the normal approximation to find a confidence
for p when we technically don't know the standard deviation (since we need
to know p to know the standard deviation):

Consider the variance for one binomial trial: p(1-p). Regardless of the
true value of p, we do know that p(1-p)<=1/4. Hence if we replace p(1-p)
with 1/4 we will error by possibly making the standard deviation (of the
number of trials or of the proportion) too big. That will have the effect
of making our confidence intervals larger than they might have to be. I.E.
we will error on the side of caution.


Doug Kuhlmann (508)-749-4242
Phillips Academy
Andover, MA 01810

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

[Privacy Policy] [Terms of Use]

© The Math Forum at NCTM 1994-2018. All Rights Reserved.