Results 1 to 2 of 2

Math Help - confidence intervals

  1. #1
    Newbie
    Joined
    Jul 2009
    From
    Essexville, MI
    Posts
    5

    Unhappy confidence intervals

    this is one of my questions on my homework this week and I'm not sure I'm doing it right. The further I get in this class the more I feel lost.

    1. The amounts (in ounces) of juice in eight randomly selected juice bottles are:

    15.4 15.7 15.2 15.8 15.8 15.4 15.0 15.6

    Assuming the population of amounts in juice bottles is known to be normally distributed, create a 95% confidence interval estimate for , the mean amount of juice in all bottles.

    You will be asked to identify x-bar, s, alpha, df, t, E and the confidence interval. (3 points each)


    This is what I have come up with so far:
    X-bar = 15.488
    S = .290
    alpha = .05
    df = 7
    T =
    E =
    critical value= 1.96
    CI = (15.2456, 15.7304)

    Is this right so far? I have a partner in my class I'm working on this with and her answers are totally different than mine.
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Flow Master
    mr fantastic's Avatar
    Joined
    Dec 2007
    From
    Zeitgeist
    Posts
    16,948
    Thanks
    5
    Quote Originally Posted by rclements3 View Post
    this is one of my questions on my homework this week and I'm not sure I'm doing it right. The further I get in this class the more I feel lost.

    1. The amounts (in ounces) of juice in eight randomly selected juice bottles are:

    15.4 15.7 15.2 15.8 15.8 15.4 15.0 15.6

    Assuming the population of amounts in juice bottles is known to be normally distributed, create a 95% confidence interval estimate for , the mean amount of juice in all bottles.

    You will be asked to identify x-bar, s, alpha, df, t, E and the confidence interval. (3 points each)


    This is what I have come up with so far:
    X-bar = 15.488
    S = .290
    alpha = .05
    df = 7
    T =
    E =
    critical value= 1.96
    CI = (15.2456, 15.7304)

    Is this right so far? I have a partner in my class I'm working on this with and her answers are totally different than mine.
    Your critical value is wrong but somehow you got the correct confidence interval ....??
    The critical value of T is 2.3646, not 1.96 (that's the critical value for Z. And you realise that Z is not used because the population sd is not known).
    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