Results 1 to 2 of 2

Math Help - Check my work regarding probability, mean, variance, standard deviation?

  1. #1
    Junior Member
    Joined
    Feb 2008
    Posts
    62

    Check my work regarding probability, mean, variance, standard deviation?

    S is the sample space and it include all possible 2x2 binary matrices. Each entry (i.e. 0 or 1) both have the same probability of appearing, 1/2. Let X be a random variable that equals the determinant of much a matrix.

    a) How many matrices are in S?
    2^4 = 16

    b) Make a list of all the matrices and find the determinants.
    I did this part and found there are 10 with 0 as the determinate, 3 with 1 as determinate, and 3 with -1 as determinate.

    c) What is the probability of each value of X?
    0 is 10/16
    -1 is 3/16
    1 is 3/16

    d) Find the mean, variance, and std deviation.
    mean=0
    variance=6/16
    std dev= sqrt(6)/4

    Look ok?
    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 Mattpd View Post
    S is the sample space and it include all possible 2x2 binary matrices. Each entry (i.e. 0 or 1) both have the same probability of appearing, 1/2. Let X be a random variable that equals the determinant of much a matrix.

    a) How many matrices are in S?
    2^4 = 16

    b) Make a list of all the matrices and find the determinants.
    I did this part and found there are 10 with 0 as the determinate, 3 with 1 as determinate, and 3 with -1 as determinate.

    c) What is the probability of each value of X?
    0 is 10/16
    -1 is 3/16
    1 is 3/16

    d) Find the mean, variance, and std deviation.
    mean=0
    variance=6/16
    std dev= sqrt(6)/4

    Look ok?
    a) is correct. I haven't bothered doing (b). Your answers to (c) are consistent with your answers to (b) and your answers to (d) are consistent with those in (c).
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Mean, Variance, and Standard Deviation
    Posted in the Statistics Forum
    Replies: 1
    Last Post: May 10th 2011, 10:34 AM
  2. Variance, and Standard Deviation
    Posted in the Advanced Statistics Forum
    Replies: 3
    Last Post: November 11th 2009, 09:13 PM
  3. Variance and STandard deviation
    Posted in the Statistics Forum
    Replies: 1
    Last Post: December 8th 2008, 06:16 PM
  4. Mean, Standard Deviation & Variance
    Posted in the Statistics Forum
    Replies: 3
    Last Post: December 31st 2007, 03:29 AM
  5. variance and standard deviation
    Posted in the Statistics Forum
    Replies: 3
    Last Post: August 7th 2007, 01:03 PM

Search Tags


/mathhelpforum @mathhelpforum