Results 1 to 2 of 2

Math Help - Variance

  1. #1
    Riceball
    Guest

    Variance

    The fomula u = x + 20 is used to find the standard deviation of the values of x given in a frequency table. It is found that "summation Fi = 40", "summation ui fi = 112 and "summation ui squared fi = 10208. Find the variance and mean values of x.



    im so confused about the u = x +20
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Super Member malaygoel's Avatar
    Joined
    May 2006
    From
    India
    Posts
    648
    there is no effect on variance by the change u=x+20

    variance of u= \frac{1}{n}(\sum_{i=1}^{n}(u_i-u_{mean})^2*f_i)
    n=\sumf_i=40
    solving we get
    variance of u=248.44
    hence, variance of x=248.44

    Keep Smiling
    Malay
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Help with variance
    Posted in the Advanced Statistics Forum
    Replies: 2
    Last Post: September 3rd 2011, 02:53 AM
  2. variance of the sample variance
    Posted in the Advanced Statistics Forum
    Replies: 3
    Last Post: February 8th 2011, 09:35 PM
  3. How to get new variance given old variance and average
    Posted in the Advanced Statistics Forum
    Replies: 0
    Last Post: November 23rd 2010, 06:39 AM
  4. Variance Help
    Posted in the Statistics Forum
    Replies: 2
    Last Post: August 23rd 2009, 02:22 PM
  5. Variance of the population variance.
    Posted in the Advanced Statistics Forum
    Replies: 2
    Last Post: November 10th 2008, 10:07 AM

Search Tags


/mathhelpforum @mathhelpforum