Results 1 to 2 of 2

Math Help - Normal Distribution PRoblems

  1. #1
    Newbie
    Joined
    Jan 2007
    Posts
    8

    Normal Distribution PRoblems

    (1) The weight W of a person is 100 kg. Unforunately, the weighing machine is not accurate. Suppose the reading R is given by the expression R = W + E where E is the error in the machine and has normal distribution with mean 0 and std. dev. 2.

    (a) what is the distribution of the reading given by the weighing machine?

    (c) What is the probability that the reading is 2kg more than what the person actually weighs?
    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 thefirsthokage View Post
    (1) The weight W of a person is 100 kg. Unforunately, the weighing machine is not accurate. Suppose the reading R is given by the expression R = W + E where E is the error in the machine and has normal distribution with mean 0 and std. dev. 2.

    (a) what is the distribution of the reading given by the weighing machine?
    N(W, 4) (normal with mean W and variance 4)

    (c) What is the probability that the reading is 2kg more than what the person actually weighs?
    2kg is 1 sigma, so we are asking that the probability of z=(R-W)/sigma
    (which has a standard normal distribution) be greater that 1. So we look
    1 up in the cumulative standard normal distrinution to find

    P(z<=1) = 0.8413,

    then:

    P(z>1) = 1-0.8413 = 0.1587

    RonL
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Problems about Normal Distribution
    Posted in the Statistics Forum
    Replies: 1
    Last Post: November 22nd 2010, 01:32 AM
  2. Normal Distribution problems
    Posted in the Statistics Forum
    Replies: 3
    Last Post: October 11th 2009, 05:58 PM
  3. Normal Distribution problems..please help..
    Posted in the Advanced Statistics Forum
    Replies: 2
    Last Post: February 23rd 2009, 06:31 AM
  4. Replies: 4
    Last Post: November 17th 2008, 12:07 PM
  5. Question about normal distribution problems
    Posted in the Advanced Statistics Forum
    Replies: 2
    Last Post: October 7th 2007, 01:19 AM

Search Tags


/mathhelpforum @mathhelpforum