Failure in the wifi service occurs at a mean rate of 3 instances per day, and the transmission on a day is consider “bad” if there are at least 5 failures that day.
(a)Immediately after a total of 7 days of bad transmission, the user will receive a discount. Find the probability that a person receives a discount for the first time on the 30th day after he started to use the service
probability?
2015-12-03 11:43 am
回答 (1)
2015-12-09 5:14 am
mean=3
P(X>5 or X=5)
=1-P(X=0)-P(X=1)-P(X=2)-P(X=3)-P(X=4)
=1-(3^0)(e^-3)/0!-(3^1)(e^-3)/1!-(3^2)(e^-3)/2!-(3^3)(e^-3)/3!-(3^4)(e^-3)/4!
=0.184736755
P=(30C7)(0.184736755)^(7) (1-0.184736755)^(30-7)
P=0.136288477
P(X>5 or X=5)
=1-P(X=0)-P(X=1)-P(X=2)-P(X=3)-P(X=4)
=1-(3^0)(e^-3)/0!-(3^1)(e^-3)/1!-(3^2)(e^-3)/2!-(3^3)(e^-3)/3!-(3^4)(e^-3)/4!
=0.184736755
P=(30C7)(0.184736755)^(7) (1-0.184736755)^(30-7)
P=0.136288477
收錄日期: 2021-04-18 14:07:15
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20151203034351AA0moq5