Re: Every time ..., was Re: General formula

[Ben Laurie <ben@xxxxxxxxxxxxx>]

Ed Gerck wrote:
> 
> Ben Laurie wrote:
> 
> > Ed Gerck wrote:
> > > This also means that if you call someone and it is busy, you could call
> > > right afterwards (just add the round-trip total delay time -- say, 5 sec)
> > > and your sucess rate should be the same as if you would wait some
> > > minutes (as people normally do).
> > >
> > > The reason in both cases is simple -- since phone statistics is given by
> > > a Poison distribution and you don't know when the conversation actually
> > > *started*, its end does not depend on the duration of your observation.
> >
> > I don't believe this for a moment. To take an extreme example, if people
> > make, on average, 1 phone call a year, with a mean duration of 1 minute,
> > then it is intuitively obvious that if I wait a day after they are busy,
> > I have an almost 100% chance that they won't be busy,
> 
> Ben Laurie:
> 
> Is this how people really use the phone where you live? Is this "phone
> statistics"? C'mon, give me a break-- and realize that the statistics of
> your "extreme example" (what an understatement) is not even given by
> a Poisson pdf.

That's the whole point: phone statistics don't follow a Poisson pdf for
an individual user. The Poisson pdf applies to the phone system as a
whole (i.e. the combined statistics for all users). Naturally for an
individual user the call frequency and duration are unrelated (i.e. not
Poisson).

> 
> > whereas 5 seconds
> > later the chances are noticably less than 100%. Of course, I believe the
> > second statement, but the first is not a consequence of it, IMNSHO.
> >
> > You're just making this stuff up as you go along, aren't you?
> 
> You remind me of a guy that drowned in a lake that had just one inch
> of water depth, on average. Just too bad he did not realize it was an
> average, though. Or, even, what an average was.
> 
> Since phone traffic statistic is hardly on-topic here, I might help you off
> list if you consider this important for your understanding of certificate
> lifetimes.
> 
> And, Ben, next time you don't understand something, just ask and say what
> part of my text you did not understand. You don't need to become aggressive
> in order to receive my reply.

But I did understand it, I simply don't believe it is correct. In
particular, the statement "since phone statistics is given by a Poison
distribution" is incorrectly used to support an argument about a single
phone user.

However, I do apologise to you and the list for the tone I used.

Cheers,

Ben.

--
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