Comments on: Calculating confidence intervals

By: Peggy

Peggy — Mon, 24 Oct 2011 23:03:07 +0000

A 95% cl between between11 and19 means?

By: jinee

jinee — Thu, 13 Oct 2011 04:26:05 +0000

a surver is conducted on a random sample of 400 americans from the entire American population. Eighty percent (80%) of the respondents agreed with the statement that social secirity benefits should not be taxed and 20% said they should be taxed. At a confidence level of 95%, what is the confidence interval, expressed as 80% +/- confidence interval?

By: Preetha RAmakrishnan

Preetha RAmakrishnan — Wed, 12 Oct 2011 10:37:06 +0000

The explanation was clear and useful

By: Maria

Maria — Tue, 27 Sep 2011 15:28:15 +0000

How can i calcualte CI for non-parametric tests, e.g. Mann U

By: Josh

Josh — Fri, 05 Nov 2010 07:08:28 +0000

Thank you! So many stat website are completely opaque. This gives me (an undergraduate, BioStats student) enough information to understand the concept and enough explanation to practically apply. You’re great! Do more

By: deb

deb — Tue, 05 Oct 2010 08:26:13 +0000

sorry I mean CI’s for log regression predictors??

By: deb

deb — Tue, 05 Oct 2010 08:25:40 +0000

Could I use the above equation to calculate logistic regression predictor variables?

By: Dave Higgins

Dave Higgins — Thu, 05 Aug 2010 14:10:34 +0000

"t is found in look-up tables (reach for your closest stats book)": the shape of the t distribution depends on the number of degrees of freedom. So, in this problem, t is not calculated, it's looked up. I suppose you could calculate it from the equation for t-distribution (e.g. see Mathworld or Wikipedia).