ECSE-2500 Engineering Probability, RPI, Spring 2011 Home Page
Homework 5, due 2pm Tues Mar 1, 2011
Notes
- Email your solutions, as a PDF file, to
wrfranklin+homeworkATgmail.com , replacing AT with @.
- You may do this homework in teams of two people.
- Put the homework number, your names and RCS-IDs on the homework. (E.g. I would say something like Homework 3, W. Randolph Franklin, frankwr.)
- Please put HW05 in your subject line.
- This homework will be graded by Hang.
- Hang Zhang's office hours are: Mon 7:10-8pm (or as long as people are there asking questions), and Wednesday at 10:00-11:10am in ECSE flip flop lounge.
Questions
- The player tosses a fair coin 5 times and counts the number of heads,
k. His reward, Y, is k2.
- (5 pts) Write the pmf of Y.
- (5) What is E[Y]?
- (5) What is Var[Y]?
- A transmission channel introduces an error 5% of the time. It
transmits 10 messages. Let X be the number of errors.
- (5) What is the pmf of X?
- (5) What is the probability of 2 or fewer errors?
- (5) What is E[X]?
- (5) What is Var[X]?
- Look at example 3.19 on page 108
- (5) Redo it, but now with p=1/2.
- (10) Do a plot of the fraction of packets dropped as function of p, for 0<=p<=1. Use the computer tool of your choice.
- We are picking two independent discrete random variables, X and Y, uniformly in the interval
[0,4]. That means that for both X and Y, S={0,1,2,3,4}.
- (5) What is E[X]?
- (5) What is Var[X]?
- (5) What is E[X+Y]?
- (5) What is Var[X+Y]?
- (5) What is E[X|X>Y]?
- (5) What is Var[X|X>Y]?
- During the Perseid meteor shower, assume that meteors are independent, and
that, on average, there is one per minute. Let X be the number of
meteors in 3 minutes.
- (5) What is the pmf of X?
- (5) What is E[X]?
- (5) What is the probability that X=0?