Results 1 to 3 of 3

Math Help - Confidence levels

  1. #1
    Newbie
    Joined
    Aug 2009
    Posts
    23

    Confidence levels

    An exporter of Ginseng Tea claims that the average weight of packets
    of Ginseng Tea is 20 g. A random sample of 36 packets of ginseng tea
    was collected. From the sample, the average weight was calculated as
    19.35 g. The population standard deviation of the weights is known to
    be 1.8 g. The weights are normally distributed.
    i. Calculate the 95% confidence interval for the population average
    weight.
    ii. Estimate the range for the total weight of 50 randomly selected packets of Ginseng tea with 95% confidence.
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Super Member
    Joined
    Jul 2009
    Posts
    593
    Thanks
    4
    What part of the problem is giving you pause? Theres not a whole lot of background, so don't really know how much to go into this problem.
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Newbie
    Joined
    Aug 2009
    Posts
    23
    (i)
    Sample mean = 19.35
    Standard deviation = 1.8
    Standard error of mean = σ / √ n
    Standard error of mean = 1.8 / √ 36
    SE = 1.8/6
    Standard error of mean 0.3
    Confidence interval 19.35-(0.3)(1.96)
    and 19.35+(0.3)(1.96)
    95 % confidence interval is (18.762, 19.938)

    (ii)Sample mean = 19.35
    Standard deviation = 1.8
    Standard error of mean = σ / √ n
    Standard error of mean = 1.8 / √ 50
    SE = 1.8/7.1
    Standard error of mean 0.25
    Confidence interval 19.35-(0.25)(1.96)
    and 19.35+(0.25)(1.96)
    95 % confidence interval is (18.86, 19.84)

    Hows this?
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. types of variables vs levels of measurments
    Posted in the Advanced Statistics Forum
    Replies: 3
    Last Post: May 17th 2010, 07:44 PM
  2. Confidence Levels
    Posted in the Advanced Statistics Forum
    Replies: 1
    Last Post: August 15th 2009, 11:04 PM
  3. Estimating the mean using confidence levels
    Posted in the Advanced Statistics Forum
    Replies: 3
    Last Post: July 15th 2009, 12:26 AM
  4. Singificance levels, critical values and p-value. Help!!!!
    Posted in the Advanced Statistics Forum
    Replies: 3
    Last Post: May 25th 2009, 07:54 AM
  5. [SOLVED] Sets - Very urgent (O levels/GCSE)
    Posted in the Math Topics Forum
    Replies: 1
    Last Post: September 19th 2007, 08:41 AM

Search Tags


/mathhelpforum @mathhelpforum