Results 1 to 3 of 3

Math Help - Confidence Intervals

  1. #1
    Newbie
    Joined
    Aug 2009
    Posts
    23

    Confidence Intervals

    Q.A research desires to identify the mean age of full-time students in a university. A random sample of 400 surveyed students indicates a mean age of 26.2 years, with a standard deviation of 5.6 years. If you were asked to interpret this data at a confidence level of 95%, what would your confidence interval be? Assume a normal distribution for the variable being investigated.


    A. I know 95% = 1.96

    I dont really know which formula im supposed to use its not z = (X - μ) / σ is it?
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Junior Member
    Joined
    Aug 2009
    Posts
    29
    Let \bar{x} = 26.2, s=5.6, and n=400. Then the 95% confidence interval is [\bar{x} - \frac{1.96 s}{\sqrt{n}},\bar{x} + \frac{1.96 s}{\sqrt{n}}] = [25.6512, 26.7488].

    More precisely, you would have to use 1.96591 instead of 1.96.
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Newbie
    Joined
    Aug 2009
    Posts
    23
    Thank you
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Confidence Intervals #2
    Posted in the Statistics Forum
    Replies: 3
    Last Post: April 22nd 2011, 03:33 AM
  2. Confidence Intervals...
    Posted in the Statistics Forum
    Replies: 1
    Last Post: April 21st 2010, 11:41 PM
  3. confidence intervals
    Posted in the Advanced Statistics Forum
    Replies: 2
    Last Post: April 13th 2010, 08:31 AM
  4. Confidence intervals #2
    Posted in the Statistics Forum
    Replies: 1
    Last Post: February 19th 2010, 01:22 AM
  5. Confidence Intervals
    Posted in the Statistics Forum
    Replies: 0
    Last Post: May 26th 2009, 07:53 AM

Search Tags


/mathhelpforum @mathhelpforum