Results 1 to 3 of 3

Math Help - Homework

  1. #1
    Newbie
    Joined
    Mar 2008
    Posts
    5

    Smile Homework

    8.46 A random sample of 10 miniature Tootsie Rolls was taken from a bag. Each piece was weighed on a very accurate scale. The results in grams were
    3.087 3.131 3.241 3.241 3.270 3.353 3.400 3.411 3.437 3.477

    (a) Construct a 90 percent confidence interval for the true mean weight.

    (b) What sample size would be necessary to estimate the true weight with an error of 0.03 grams with 90 percent confidence?

    (c) Discuss the factors which might cause variation in the weight of Tootsie Rolls during
    manufacture. (Data are from a project by MBA student Henry Scussel.)


    8.62 In 1992, the FAA conducted 86,991 pre-employment drug tests on job applicants who were to be engaged in safety and security-related jobs, and found that 1,143 were positive.

    (a) Construct a 95 percent confidence interval for the population proportion of positive drug tests.

    (b) Why is the normality assumption not a problem, despite the very small value of p? (Data are from Flying 120, no. 11 [November 1993], p. 31.)
    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 Aala View Post
    8.46 A random sample of 10 miniature Tootsie Rolls was taken from a bag. Each piece was weighed on a very accurate scale. The results in grams were
    3.087 3.131 3.241 3.241 3.270 3.353 3.400 3.411 3.437 3.477

    (a) Construct a 90 percent confidence interval for the true mean weight.

    (b) What sample size would be necessary to estimate the true weight with an error of 0.03 grams with 90 percent confidence?

    (c) Discuss the factors which might cause variation in the weight of Tootsie Rolls during
    manufacture. (Data are from a project by MBA student Henry Scussel.)

    [snip]
    The identical question (asked by an ostensibly different member) was asked and discussed here.

    And cop this.
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Flow Master
    mr fantastic's Avatar
    Joined
    Dec 2007
    From
    Zeitgeist
    Posts
    16,948
    Thanks
    5
    Quote Originally Posted by Aala View Post
    [snip]In 1992, the FAA conducted 86,991 pre-employment drug tests on job applicants who were to be engaged in safety and security-related jobs, and found that 1,143 were positive.

    (a) Construct a 95 percent confidence interval for the population proportion of positive drug tests.

    (b) Why is the normality assumption not a problem, despite the very small value of p? (Data are from Flying 120, no. 11 [November 1993], p. 31.)
    (a) n = 86991.

    Sample proportion: \hat{\theta} = \frac{1143}{86991}.

    True proportion: \theta.

    95% confidence interval: \hat{\theta} - 1.96 \sqrt{\frac{\hat{\theta}(1 - \hat{\theta})}{n}} < \theta < \hat{\theta} + 1.96 \sqrt{\frac{\hat{\theta}(1 - \hat{\theta})}{n}}.

    (b) n is large.
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. homework help
    Posted in the Discrete Math Forum
    Replies: 4
    Last Post: August 31st 2009, 05:36 AM
  2. need help with homework
    Posted in the Trigonometry Forum
    Replies: 5
    Last Post: July 20th 2009, 09:34 AM
  3. homework help
    Posted in the Algebra Forum
    Replies: 2
    Last Post: February 10th 2009, 08:12 PM
  4. Homework Help
    Posted in the Calculus Forum
    Replies: 1
    Last Post: November 2nd 2007, 02:09 PM
  5. Homework Help
    Posted in the Math Topics Forum
    Replies: 9
    Last Post: October 14th 2007, 04:00 PM

Search Tags


/mathhelpforum @mathhelpforum