Introduction to Statistical Quality Control
7th Edition
ISBN: 9781118146811
Author: Montgomery, Douglas C.
Publisher: John Wiley & Sons Inc
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Chapter 3, Problem 42E
A computer system uses passwords consisting of the lowercase letters (a–z) and the integers (0–9). There are 10,000 users with unique passwords. A hacker randomly selects (with replacement) passwords in an attempt to break into the system.
- (a) Suppose that 8000 of the users have six-character passwords. What is the
mean and standard deviation of the number of attempts required before the hacker selects a legitimate password? - (b) Suppose that 2000 of the users have three-character passwords. What is the mean and standard deviation of the number of attempts required before the hacker selects a legitimate password?
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Chapter 3 Solutions
Introduction to Statistical Quality Control
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