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Phishing attacks to e-mail accounts. Refer to the Chance
Chapter 4, Problem 148E(choose chapter or problem)
Problem 148E
Phishing attacks to e-mail accounts. Refer to the Chance (Summer 2007) article on phishing attacks at a company, Exercise 2.33 (p. 62). Recall that phishing describes an attempt to extract personal/financial information through fraudulent e-mail. The company set up a publicized e-mail account—called a “fraud box”—that enabled employees to notify them if they suspected an e-mail phishing attack. If there is minimal or no collaboration or collusion from within the company, the interarrival times (i.e., the time between successive e-mail notifications, in seconds) have an approximate exponential distribution with a mean of 95 seconds.
a. What is the probability of observing an interarrival time of at least 2 minutes?
b. Data for a sample of 267 interarrival times are saved in the accompanying file. Do the data appear to follow an exponential distribution with θ = 95?
Questions & Answers
QUESTION:
Problem 148E
Phishing attacks to e-mail accounts. Refer to the Chance (Summer 2007) article on phishing attacks at a company, Exercise 2.33 (p. 62). Recall that phishing describes an attempt to extract personal/financial information through fraudulent e-mail. The company set up a publicized e-mail account—called a “fraud box”—that enabled employees to notify them if they suspected an e-mail phishing attack. If there is minimal or no collaboration or collusion from within the company, the interarrival times (i.e., the time between successive e-mail notifications, in seconds) have an approximate exponential distribution with a mean of 95 seconds.
a. What is the probability of observing an interarrival time of at least 2 minutes?
b. Data for a sample of 267 interarrival times are saved in the accompanying file. Do the data appear to follow an exponential distribution with θ = 95?
ANSWER:
Step 1 of 4
The time between successive email notifications (interarrival times) have an exponential distribution with a mean of 95 seconds.
The frequency distribution graph is given.
We have to find,
(a) The probability of observing an interarrival time of at least 2 minutes,
(b) Do the data appear to follow an exponential distribution with .