Question

You may be familiar with the famous murder trials involving athletes Pistorius and OJ Simpson. One of the significant arguments was related to their past violent behavior. Specifically here is a quote from an article

“Pistorius had been arrested in 2009 for violent conduct involving a young woman, and he was also once investigated for illegal ownership of .38 caliber ammunition that defense lawyers said belonged to his father. An autopsy meanwhile found no signs of physical violence on Steenkamp'sbody.
In Simpson's case, the prosecution spent the opening weeks of the trial presenting evidence that the former San Francisco 49s running back had a history of physically abusing Nicole Simpson. Defense lawyer Alan Dershowitz argued only a tiny fraction of women abused by their mates are murdered.”

Use this Discussion Board forum (each student creates a new thread, gives a suitable title and records their thoughts in that post) to discuss the arguments (in favor or against) and the probability that is being evaluated in the above statements. You need not crunch any numbers. Just discuss what probability they are talking about and how it could be evaluated. Is it as simple as answering the question - "What is the probability that the accused murdered the victim"? What should be the probability that they should be calculating? Can we use conditional probability here? What will be the "condition"?

Answer 1

OJ Simpson – This is a very interesting case when we look at the facts of the case. If we look at the majority of the evidence, it seems that the ultimate culprit of committing the crime is none other than OJ Simpson, but in the court of law, he was declared innocent. If we look at the probability or conditional probability, then I would suggest that one should not implement the probability in the case as a reference. In fact, the base of the case should be, did OJ really commit the crime? This must be verified on the basis of the evidence.

The probability can be applied most efficiently if we want to determine the percentage of the battered women who were murdered by the husbands. Conditional probability can be defined as “ the chance of occurrence of an event provided the other events are true or they have already being happened.” If we look at this definition, it is quite obvious that the claim made by Dershowitz that the percentage of battered women who were killed by their husbands is quite low.

After going through the number of researches available online and when Bayes’ formula is applied, there are almost 90% of battered women who were killed by their husbands but it was regarded as only 1% by Dershowitz. In my opinion, court’s decision was not an accurate one and the case must be seen by the jury by having a close analysis of the statistics and try to figure out the conditional probability while making the decision.

The Pistorius case – As opposed to OJ Simpson case, he was found guilty of murdering his girlfriend and in my opinion, this decision is also questionable. Pistorius thought that his girlfriend is taking rest in the bed and there was an intruder in the house. In my opinion, the concept of conditional probability should have been used in this case by the prosecution. Looking at the testimonies and texts, Pistorius was found that he was abusive with his girlfriends in the past. If we look at the stats provided in the OJ Simpson, it was found that almost 90% of battered women are killed by their husbands but these stats do not hold in the case of Pistorius. In fact, this stats was not used in the case and he was declared as guilty of murdering his girlfriend.

If I look at the statistical data and conditional probability, I have sincere doubts about the decision of the court in both cases. This is true that while trialing, the importance of evidence is quite critical, but while judging the status of mind of a person, stats and pas behavior must be visited.