View Single Post
  #2  
Old June 30th, 2009, 05:04 PM
mr fantastic's Avatar
mr fantastic mr fantastic is online now
Flow Master

 
Join Date: Dec 2007
Location: Zeitgeist
Posts: 12,239
Country:
Thanks: 2,575
Thanked 4,762 Times in 4,194 Posts
mr fantastic has a reputation beyond reputemr fantastic has a reputation beyond reputemr fantastic has a reputation beyond reputemr fantastic has a reputation beyond reputemr fantastic has a reputation beyond reputemr fantastic has a reputation beyond reputemr fantastic has a reputation beyond reputemr fantastic has a reputation beyond reputemr fantastic has a reputation beyond reputemr fantastic has a reputation beyond reputemr fantastic has a reputation beyond repute
Default

Quote:
Originally Posted by chromium View Post
Hello all! I would really appreciate some help. I kind of used an equation that seemed to work.

If I have 9 observations, specifically 240,216,265,284,229,232,250,225,252, and need to find a 95% confidence interval for the mean \mu assuming that these are observations of a N(\mu,\sigma^{2}) distribution, can I do the following?:

(\bar{x}-t_{\alpha/2}\frac{s}{\sqrt{n}}, \bar{x}+t_{0.025,8}\frac{s}{\sqrt{n}})
*I think \alpha/2 becomes 0.025 with 8 degrees of freedom and therefore t_{\alpha/2}=2.306

(243.66667-2.306\frac{21.418449999}{\sqrt{9}}, 243.66667+2.306\frac{21.418449999}{\sqrt{9}})
(227.20, 260.13)
The theory looks OK, I haven't checked the fine detail (where the devil always is). A thread of relevance: constructing a confidence interval please help
__________________
There are two things you should never try to prove: the impossible and the obvious.

The greater danger for most of us lies not in setting our aim too high and falling short; but in setting our aim too low and achieving our mark. (Michelangelo Buonarroti)

  • To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

  • To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

  • To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

  • To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

  • To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
Reply With Quote