(Probability Distribution, Mean, and Standard Deviation.) An article in Informat
ID: 3205045 • Letter: #
Question
(Probability Distribution, Mean, and Standard Deviation.) An article in Information Security Technical Report ("Malicious Software-Past, Present and Future" (2004, Vol. 9, pp. 6-18)] provided the following data on the top 10 malicious software instances for 2002. The clear leader in the number of registered incidences for the year 2002 was the Internet worm "Klez, " and it is still one of the most widespread threats. This virus was first detected on 26 October 2001. and it has held the top spot among malicious software for the longest period in the history of virology. The 10 most widespread malicious programs for 2002 Suppose that 20 malicious software instances are reported. Assume that the malicious sources can be assumed to be independent. (a) What is the probability that at least one instance is "Klez?" (b) What is the probability that three or more instances arc not "Klez?" (c) What are the mean and standard deviation of the number of "Lentin" instances among the 20 reported? Bonus! What are the mean and standard deviation of the number of not "Lentin" instances among the 20 reported? Comparing with (c), what is your observation?Explanation / Answer
a) Here you are ask to find the probability of at least one instance is Klez
= P( 1 and more instance is Klez)
=P( 1 instance is Klez) Here only one instance is Klez
= 0.6122 In problem you are given in percentage 61.22% just devide by 100 you get probability.
b) P( 3 or more is not Klez) =1 - P( 1 or 2 Klez ) = 1 - P( 1 Klez )=1-0.6122=0.3878
c) Here n=number of reported =20 , p=probability of Lentin =0.2052 .
This follows binomial distribution with mean = n*p =20*0.2052=4.104
And standard deviation =sqrt ( n *p*q) = sqrt (20*0.2052*0.7948)=1.8060
Bonus : Not latin probability is p =0.7948 , n=20
mean=n*p=20*0.7948=15.896
Standard deviation =sqrt ( n*p*q) =sqrt(20*0.7948*0.2052)=1.8060
Here observations are not latin instance
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.