Seminar at Simon Bolivar University: Two presentations

September 12, 2004

Besides the overview presentation by Isabel Llatas, there were two talks at this first seminar:


1)      Statistical study of the CNE data by Bernardo Marquez et al.


 


This is a group of engineers which looked at the statistical properties of the electronic results at the two lowest levels of detail, at the Center level and at the parish level.


 


Basically, the CNE divided the nation into 321 municipalities. Each municipality was divided itself into parishes and the parishes into centers. There were on average 2.6 parishes per municipality and on average there were 5.4 centers per parish. There were on average 10,098 votes per center and 26,486 votes per parish.


 


The study was a statistical hypothesis testing of all of the CNE data. The basic hypothesis was that the CNE data is valid and thus by looking at averages an standard deviations one should be able to establish confidence levels at both the parish and the center level, in terms of votes within a parish or center being in the correct range. By this, it means that they look at the final result of a machine and check whether that result is within what is expected from the statistics of the center or the parish.


 


The authors found that with a 95% confidence level, there are only 7% of the machines at the center level which show unexpected results with respect to the center. In contrast, they found that 62% of the parishes showed unexpected results. If the confidence level was 99% they found 51% of the machines had unexpected results.


 


They then looked at each parish to see how much centers differed within a parish by looking at the standard deviations of each center. Then, they eliminated what they called the non-homogenous centers, those in which the centers within a parish showed significant differences in the standard deviations of the distributions. Thus, they kept only the “homogeneous” parishes and found that with a 95% level of confidence 42% of the machines showed unexpected results and with 99% confidence 26% of the machines showed unexpected results.


 


2)      A study of the coincidences in the votes in the machine by Raul Jimenez (USB), Alfredo Marcano (USB) and Juan Jimenez (UCV)


 


This talk discussed the various simulations that have been done to study the coincidences. It was very critical of Rubin’s and Taylor’s form the technical point of view. I must say that what I was not able to understand the details of what they did, it was beyond my understanding and I tried. Basically, they are using fairly sophisticated mathematical theory to look at the problem and study probabilities of occurrences.


 


In their most detailed work, they looked at the probability of SI and No coincidences as well as the probability that the sum of the Si and No votes also coincides. They obtained a probability of 3.5 in 10,000 for the SI coincidences, reasonable (I think it was 0.3) for the NO and 1 in 1,000,000 for the sum of SI and No to coincide. 


 


This result is being submitted as a scientific paper to a journal next week and the author said he will send me a copy when he send it in to the Journal.

Leave a comment