Quiz6 with soln - Quiz 6 October 27 Print your name here...

Info icon This preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon
Quiz 6 October 27 Print your name here: ___________________________ ID #__________ (use all UPPER CASE letters) ______1. Suppose that X has mean μ =2 and σ =1 and Y= 3- 2X. The standard deviation of Y equals_____ _____2. Suppose that X 1 and X 2 have mean μ =5 and σ 2 = 4 and Cov(X j , X k ) =0 for j k . Then the variance of Y= X 1 –X 2 equals_______ 3-4. Suppose we take a random sample of n=4 values of X. We let X 1 denote the first value in the sample, X 2 denote the second value, X 3 denote the 3 rd value and X 4 denote the 4 th value. Given (1) μ 1 = μ 2 = μ 3 = μ 4 = μ x = 8 and (2) σ 1 = σ 2 = σ 3 = σ 4 2 x =10. Let 4 4 1 = = i i X X . Because each of the Xj are random variables, X is a random variable. _______ 3. The mean value of X equals____ ________ 4. If the population size, N>> 4 then Cov(X j , X k ) = 0 for all j ≠k and the X j are independent, so Var( X ) = ____ 1
Image of page 1

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
SOLUTIONS TO QUIZ 6 ___ 2 ___ 1. Suppose that X has mean μ =1 and σ =1 and Y= 3- 2X. The standard deviation of Y equals_____ Y= 3-2X. If Y=aX + b then  σ 2 Y  = a 2 σ 2 x   and  σ =|a| σ X Here a=-2,  so |a| =2,  and  σ x  =1. So 
Image of page 2
Image of page 3
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern