{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

fall 2005 STAT 230 test4soln

# fall 2005 STAT 230 test4soln - STAT 230 Test#4 November 8...

This preview shows pages 1–2. Sign up to view the full content.

STAT 230 Test #4 November 8, 2005 4:30 – 5:15 pm 1. Two numbers U and V are randomly selected from 1, 2 and 3 with replacement . Let X = min { U, V } and Y = max { U, V } . [4] (a) Find the two missing values of the joint probability function of ( X, Y ) in the following table: x f ( x, y ) 1 2 3 1 1/9 0 0 y 2 2/9 (1/9) 0 3 2/9 (2/9) 1/9 [5] (b) Find the marginal probability function of Y . y 1 2 3 f Y ( y ) 1 / 9 1 / 3 5 / 9 [5] (c) Find the conditional probability P ( Y = 2 | X = 1). P ( Y = 2 | X = 1) = f (1 , 2) f X (1) = 2 / 9 5 / 9 = 2 5 . [3] (d) Are X and Y independent? Why or why not? X and Y are not independent, since f X (1) × f Y (1) = (5 / 9) × (1 / 9) 6 = f (1 , 1). ( Note : this inequality can be replaced by other similar ones; Another acceptable answer is “ X and Y are not independent, since X Y ”) 2. In a public opinion survey over a large population, each respondent chooses one and only one answer from five possible answers: A. Strongly Agree; B. Agree; C. Disagree; D. Strongly Disagree; E. Don’t Know. For a randomly selected individual, the probabilities that he/she chooses one of the five answers are listed in the following table.

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

View Full Document
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

### What students are saying

• 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.

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

• 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.

Dana University of Pennsylvania ‘17, Course Hero Intern

• 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.

Jill Tulane University ‘16, Course Hero Intern