Results 1 to 2 of 2

Math Help - Estimating Mean & Standard deviation from a cumulative frequency curve

  1. #1
    Newbie
    Joined
    May 2010
    Posts
    2

    Estimating Mean & Standard deviation from a cumulative frequency curve

    How would you go about estimating the mean and the standard deviation from a cumulative frequency curve, if the only data points you know for certain are the 10th, 50th and 90th percentile? I've determined that the distribution is right-skewed, but can't figure out how i would estimate the mean and the sd.

    any help will be greatly appreciated!
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Grand Panjandrum
    Joined
    Nov 2005
    From
    someplace
    Posts
    14,972
    Thanks
    4
    Quote Originally Posted by mathiscruel View Post
    How would you go about estimating the mean and the standard deviation from a cumulative frequency curve, if the only data points you know for certain are the 10th, 50th and 90th percentile? I've determined that the distribution is right-skewed, but can't figure out how i would estimate the mean and the sd.

    any help will be greatly appreciated!
    In what context has this arisen? If it is a home work problem what have you been covering? Do your notes say anything relevant?

    I would consider fitting a beta distribution to the given quantiles (though that will still need some side assumptions), but that is not elementary and I will not do it here.

    (a triangular distribution is probably easier to handle than the beta - look at the Wikipedia article on the triangular distribution for the cumulatve triangular distribution function.)

    CB
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Standard Deviation along a power curve
    Posted in the Advanced Statistics Forum
    Replies: 0
    Last Post: January 17th 2011, 03:44 AM
  2. Cumulative Frequency
    Posted in the Statistics Forum
    Replies: 6
    Last Post: July 8th 2010, 02:11 AM
  3. Cumulative standard deviation question
    Posted in the Statistics Forum
    Replies: 1
    Last Post: March 29th 2010, 11:06 AM
  4. Frequency Table Standard Deviation
    Posted in the Advanced Statistics Forum
    Replies: 9
    Last Post: December 12th 2009, 06:00 AM
  5. Replies: 0
    Last Post: November 7th 2008, 06:17 AM

Search Tags


/mathhelpforum @mathhelpforum