Results 1 to 4 of 4

Math Help - Compute the z or t value of the sample test statistic.

  1. #1
    Newbie
    Joined
    Dec 2008
    Posts
    2

    Compute the z or t value of the sample test statistic.

    In an article appearing in Today’s Health a writer states that the average number of calories in a serving of popcorn is 75. To determine if the average number of calories in a serving of popcorn is different from 75, a nutritionist selected a random sample of 20 servings of popcorn and computed the sample mean number of calories per serving to be 78 with a sample standard deviation of 7.
    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 mathretard View Post
    In an article appearing in Today’s Health a writer states that the average number of calories in a serving of popcorn is 75. To determine if the average number of calories in a serving of popcorn is different from 75, a nutritionist selected a random sample of 20 servings of popcorn and computed the sample mean number of calories per serving to be 78 with a sample standard deviation of 7.
    Where is the trouble in calculating t?

    You substitute the given values into the formula t = \frac{\overline{x} - \mu_0}{s/\sqrt{n}}.
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Newbie
    Joined
    Dec 2008
    Posts
    2

    additional question

    So is the answer t= 1.916 or z=1.916
    Follow Math Help Forum on Facebook and Google+

  4. #4
    Flow Master
    mr fantastic's Avatar
    Joined
    Dec 2007
    From
    Zeitgeist
    Posts
    16,948
    Thanks
    5
    Quote Originally Posted by mathretard View Post
    So is the answer t= 1.916 or z=1.916
    You cannot use z because the population variance is unknown and the sample size is small.

    I haven't checked the answer - I assume you can correctly use a calculator.
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. One sample t-test CLASHING with paired sample t-test?
    Posted in the Advanced Statistics Forum
    Replies: 0
    Last Post: February 15th 2011, 10:34 PM
  2. test statistic and probaility
    Posted in the Advanced Statistics Forum
    Replies: 1
    Last Post: May 6th 2010, 06:10 PM
  3. Z versus t statistic for small sample sizes?
    Posted in the Advanced Statistics Forum
    Replies: 1
    Last Post: October 20th 2009, 03:51 AM
  4. test statistic?
    Posted in the Advanced Statistics Forum
    Replies: 2
    Last Post: June 22nd 2009, 05:30 PM
  5. hypothesis test ,test statistic wrong!
    Posted in the Advanced Statistics Forum
    Replies: 3
    Last Post: March 28th 2009, 04:59 AM

Search Tags


/mathhelpforum @mathhelpforum