Results 1 to 1 of 1

Math Help - Mean and Variance Question

  1. #1
    Junior Member
    Joined
    Oct 2009
    Posts
    37

    Mean and Variance Question

    Hi everyone, I am stuck on this question:

    A multiple choice exam, each with 5 possible answers. One mark is awarded for a correct answer, and 1/4 mark is deducted for an incorrect answer. A particular student has probability p(i) it knowing the answer to the i-th question, independently of other questions.

    Suppose that on a question where the student does not know the answer, he or she guesses randomly. Show that his or her total mark has expectation

    Mean and Variance Question-math-capture.png
    Attached Thumbnails Attached Thumbnails Mean and Variance Question-math-capture.png  
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. variance question
    Posted in the Advanced Statistics Forum
    Replies: 0
    Last Post: September 25th 2011, 04:59 PM
  2. variance question help please.
    Posted in the Advanced Statistics Forum
    Replies: 0
    Last Post: September 13th 2011, 06:30 PM
  3. Question about variance.
    Posted in the Advanced Statistics Forum
    Replies: 1
    Last Post: January 12th 2010, 04:51 PM
  4. variance question
    Posted in the Advanced Statistics Forum
    Replies: 1
    Last Post: October 4th 2009, 05:18 PM
  5. Question of Variance
    Posted in the Advanced Statistics Forum
    Replies: 1
    Last Post: October 7th 2008, 11:38 AM

Search Tags


/mathhelpforum @mathhelpforum