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NEW YORK UNIVERSITY
DEPARTMENT OF ECONOMICS
ECONUB.18.011: Statistics, Fall 2011
HOMEWORK 4
DUE MONDAY OCTOBER 24 2011 BEFORE 5PM
in your TA’s mailbox on the 6th
f
oor, 19 West 4th Street .
Problem 1
A chain of motels has adopted a policy of giving a 3% discount
to customers who pay in cash rather than by credit cards. Its experience is
that 30% of customers of all customers take the discount. Let Y= number of
discount takers among the next twenty customers.
A)
Is Y a binomial random variable? Explain.
B)
Assuming that Y is a binomial random variable,
f
nd the probability that
exactly 5 out of 20 customers take the discount.
C)
Find the probability that at most 5 customers take a discount.
D)
What is the most probable number of discount takers in the next 20
customers?
E)
What is the expected value and standard deviation of the number of
discount takers among next 20 customers?
Problem 2
4.94/217.
Problem 3
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This note was uploaded on 11/05/2011 for the course ECON UA.18.101 taught by Professor Romanfrydman during the Fall '11 term at NYU.
 Fall '11
 RomanFrydman
 Economics

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