# Re: approximate solutions

From: Kathy Dopp <kathy_dot_dopp_at_gmail_dot_com>
Date: Fri Jul 21 2006 - 23:18:49 CDT

On 7/21/06,

> Message: 3
> Date: Fri, 21 Jul 2006 11:30:35 -0700 (PDT)
> From: "Edmund R. Kennedy" <ekennedyx@yahoo.com>
> Subject: Re: [OVC-discuss] approximate solutions
>
> Hello Jerry:
>
> Actually the graphs and tables are still quite useful
> for checking and cutting down orders of magnitude
> errors.
> While it's great to get precise solutions with
> today's calculators and computers, it's much easier to
> display how things relate to the variables with a
> graphical approximation.

Ed and Jerry,

I love graphs, but there are four independent variables (election
margin, total #vote counts, desired probability, and the assumed
maximum rate of margin-shifting per machine) and one dependent
variable - the vote count audit sample size. We could make graphs by
holding three of the independent variables fixed and vary one of the
independent variables for each graph, but you would end up with LOTS
of graphs. The three variables with the fewest real life values for
them that would be needed, would be assumed maximum margin
shift/machine, probability and candidate margin, so taking candidate
margins from 1% to say 15% and probabilities of say 90% to 98%, there
could be 15*8 =120 charts that election officials could use to look up
how many vote counts to select for audit if they have N vote counts in
their county - assuming we give them only one option for max vote
counts.

I think that you are suggesting that we could simply do something
like have 15 charts for the 15 margins of interest (assuming that all
races in a county are audited with the same sample size determined by
the race with the smallest margin -- I don't know enough yet to
conclude that would be the case with optical scan ballots that you
could sort to count, but I would assume that would have to be the best
approach with stupid DRE paper rolls) each with nine curves on them
for the nine probabilities they may want.

To do a family of curves for a family of charts to make it easy to
look up values for vote count auditing would require some
decision-making re. the range of values to use to create charts and
curves for.

I agree with you that presenting a book of charts and/or tables for
people to use to calculate vote count audit margins is a good idea
providing the "family of curves" for each desired probability or
candidate vote count margin don't overlap each other illegibly because
then say 120 charts would be needed rather than 15 - but regardless,
this is a big project that a computer would need to generate.

So we still need a program or spreadsheet that will generate the
charts for us, whether from an exact formula if we obtain one, or from
an algorithm.

A book of tables and charts may be more likely to be used than a
spreadsheet that required trial and error or even a computer program
that let users input the four independent vars and found the exact
answer - is that what you're saying?

Thanks.

Kathy

"Enlighten the people generally, and tyranny and oppressions of body
and mind will vanish like evil spirits at the dawn of day," wrote
Thomas Jefferson in 1816
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Received on Mon Jul 31 23:17:06 2006

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