[R] queue waiting times comparison

Gabor Grothendieck ggrothendieck at gmail.com
Thu Aug 18 17:08:58 CEST 2011


On Thu, Aug 18, 2011 at 10:12 AM, Petr PIKAL <petr.pikal at precheza.cz> wrote:
> Hi Jim
>
>>
>> If those values represent response times in a system, then when I was
>> responsible for characterizing what the system would do from the
>> viewpoint of an SLA (service level agreement) with customers using the
>> system, we usually specified that "90% of the transactions would have
>> a response time of --- or less".  This took care of most "long tails".
>>  So it depends on how you are planning to use this data.  We usually
>> monitored the 90th or 95th percentile to see how a system was
>> operating day to day.
>
> I get the point. This can be an option. I will discuss it with my
> colleagues.
>

Here are more plots which each show that the main mass of the
distributions are the same but the right tails differ:

# 1
plot(density(ml$y2, adjust = 2), col = 2)
lines(density(ml$y1, adjust = 2), col = 1)
legend("topright", legend = 1:2, col = 1:2, lty = 1)

# 2
qqplot(ml$y1, ml$y2, xlim = c(0, 100), ylim = c(0, 100))
abline(0, 1)

-- 
Statistics & Software Consulting
GKX Group, GKX Associates Inc.
tel: 1-877-GKX-GROUP
email: ggrothendieck at gmail.com



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