--- In [email protected], TurquoiseB <[EMAIL PROTECTED]> wrote:
>
> --- In [email protected], "sparaig" <sparaig@> wrote:
> >
> > --- In [email protected], new.morning <no_reply@> 
wrote:
> > >
> > > http://istpp.org/crime_prevention/voodoo_rebuttal.html#note1
<snip>
> > > And later, he dismisses a doubling of the murder rate during the
> > > course from 10/mo to 20/, as an "outlier". Thats convenient.

Actually that would be 10 and 20 per week, not per
month.

> > It was an outlier within the course itself. It was a one-week 
> > aberration due to a gang fight that saw 10 deaths in one 
> > incident, IIRC.
> 
> Yeah, new...it's perfectly legitimate to "not count" an
> anomalous event like *that*! What are you *thinking*?
> If you bitch about something as miniscule as disregarding
> data because it doesn't fit the all-important expectations,
> why you could set a precedent.

Actually, statistically speaking, anomalous events
are just that, anomalous, and may *not* be relevant
when one is considering longer-term trends.

This is from the article new morning cites:

Park asserts that levels of violence actually increased to record 
levels. He confuses homicides — which accounted for only 3% of 
violent crime in Washington during 1993 — with violent crimes in 
general. Park asserts that the murder rate soared during the 
experiment, and claims that "participants in the project seemed 
serenely unaware of the mounting carnage around them."

It is true the murder rate did not drop during the course — as we 
acknowledged in the initial research report and in the published 
study — but the facts were very different. For six weeks ending the 
month before the experiment, from mid-March through April, homicides 
in Washington averaged ten per week. Beginning one week after the 
course and for twelve weeks thereafter, homicides also averaged ten 
per week. During the eight weeks of the experiment, in June and July, 
the average was again ten per week — except for one horrific 36-hour 
period in which ten people died. Apart from this brief episode, which 
was a statistical outlier, the level of homicides during June and 
July of 1993 was not significantly higher than the remainder of the 
year.

According to his article, Park apparently took his lead on the murder 
issue from a Washington Post reporter who had been impressed that the 
one 36-hour period had led to a sudden doubling of the murder rate 
that week. The reporter, and Park, did not notice that the very next 
week the murder rate dropped from its common rate of ten by more than 
twice — that is, the totals went up to 20 one week and down to 4 the 
next. This is precisely the type of sporadic fluctuation one must 
account for when total numbers are small. The average incidence of 
murder in Washington was little more than one per day, and with 
numbers as low as this, as Park and all scientists know, random 
fluctuations can appear extremely high when listed as percentages.

As I said in an earlier post, I'd sure like
new morning to elucidate what he thinks is
wrong with this explanation of why the fact
that the murder rate jumped during one 36-
hour period should not be considered significant
with regard to the overall study results.



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