2003 University of Illinois at Chicago ECE 341 V. Goncharoff
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ECE 341 - Probability and Random Processes for Engineers
Homework #4 (write answers here, show work on paper stapled to this cover sheet)
Problem 1.
When a two-way paging system transmits a message, the probability that the
message will be received by the pager it is sent to is p. When the pager receives
the message, it transmits an acknowledgment signal (ACK) to the paging system.
If the paging system does not receive the ACK, it sends the message again.
Let N represent the number of times the system transmits the same message.
What is the minimum value of p necessary for 997.0]20[ =≤NP ?
Problem 2.
A new cellular phone billing plan costs $15 per month plus 10 cents for each
minute of use. If the number of minutes you use the phone in a month is a
geometric random variable with mean value = 100 minutes, what is the expected
monthly cost ][CE of the phone?
Problem 3.
Solve textbook problem 2.8.5 on page 85.
a)
b)