Probability function

  • Thread starter aurao2003
  • Start date
  • #1
126
0

Homework Statement


Hi
I am trying to solve the d, e and f parts of this problem

The discrete random variable X has probability function
where k is a positive constant.

P(X = x) ={k(2 – x), x = 0, 1, 2,
k(x – 2), x = 3,
0, otherwise,

(a) Show that k = 0.25.
(b) Find E(X) and show that E(X 2) = 2.5.
(c) Find Var(3X – 2).
Two independent observations X1 and X2 are made of X.
(d) Show that P(X1 + X2 = 5) = 0.
(e) Find the complete probability function for X1 + X2.
(f) Find P(1.3 < X1 + X2 < 3.2).

Not sure how to begin. Please help. The exam is tomorrow.



Homework Equations





The Attempt at a Solution

 

Answers and Replies

  • #2
jbunniii
Science Advisor
Homework Helper
Insights Author
Gold Member
3,393
181
For (a), what must be the answer if you sum P(X = x) over x = 0, 1, 2, 3?
 

Related Threads on Probability function

  • Last Post
Replies
5
Views
818
  • Last Post
Replies
1
Views
4K
Replies
3
Views
8K
Replies
1
Views
1K
Replies
1
Views
17K
Replies
3
Views
4K
Replies
2
Views
2K
Replies
5
Views
800
Replies
2
Views
1K
Top