Math Help Forum

Math Help Forum Feed Site Feed

Go Back   Math Help Forum > University Math Help > Advanced Probability and Statistics
Reply
 
Thread Tools Display Modes
  #1  
Old October 29th, 2009, 05:57 PM
Newbie
 
Join Date: Oct 2009
Posts: 1
Country:
Thanks: 0
Thanked 0 Times in 0 Posts
mikecupertino is on a distinguished road
Default Confidence limits for non normal distribution

Hello everyone,

I'm new to this forum. I have a question which I hope someone can answer.

I'm analyzing data from a survey (opinion survey at a local Catholic parish). The possible answers for each question are: strongly agree (1), agree (2), undecided (3), disagree (4) and strongly disagree (5). Right now, I have about 550 data points. When all surveys have been entered, I will have about 750 data points.

One of the first thing I noticed is that there is a lot more variability in some answers than others. The standard deviation of the responses varies from .6 to 1.1.

I would like to calculate confidence intervals for each question, but I'm not sure how to do it. I don't believe the responses are normally distributed. The results are very skewed to positive responses. About 69% of the responses are "agree" or "strongly agree". If I calculate a 95% confidence interval for each question as: the mean answer +/- 1.96 standard deviations, I get a range for some questions that says the answer could be anything from strongly agree to strongly disagree.

I have some statistics background and I'm comfortable doing regression analysis, but this is way beyond my statistical knowledge.

Thanks in advance for your help.

Mikecupertino
Reply With Quote
Advertisement
 
Reply

Tags
confidence intervals, non normal distribution, sampling theory

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off
Forum Jump


All times are GMT -7. The time now is 06:30 PM.


Powered by vBulletin® Version 3.7.3
Copyright ©2000 - 2009, Jelsoft Enterprises Ltd.
SEO by vBSEO 3.2.0 ©2008, Crawlability, Inc.
©2005 - 2009 Math Help Forum


Math Help Forum is a community of maths forums with an emphasis on maths help in all levels of mathematics.
Register to post your math questions or just hang out and try some of our math games or visit the arcade.