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Exponential distribution

MacDanger · 2013-11-15 23:58:41

Hi Just working on some exam questions and I'm looking for some help with part of one question. A poisson process (monitoring failures) has a rate of 1 / 4 months. Only every second failure is monitored (i.e. rate = 1/8 months or theta = 8), what is the probability that the time between monitored failures is > 9 months - I…

15-11-2013 11:58pm

#1

MacDanger

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Join Date: February 2008

Posts: 3070

Hi

Just working on some exam questions and I'm looking for some help with part of one question.

A poisson process (monitoring failures) has a rate of 1 / 4 months. Only every second failure is monitored (i.e. rate = 1/8 months or theta = 8), what is the probability that the time between monitored failures is > 9 months - I think I'm ok with this part, I used:

{1 - (1 - e^(-9/8))} = e^(-9/8) = 0.325

The second part is, supposing that instead of monitoring every 2nd failure, that failures are monitored with prob, p = 0.5 - what is the probability that the time between monitored failures is > 9 months?? How do I account for the probability of 0.5??

I was considering using the same forumla as above using theta = 4 and then dividing by 0.5? (twice??)??

Any suggestions appreciated

Thanks

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