After the completion of IDL 3 Preliminary and final assignments, you will have completed a probabilistic analysis and presented the findings in a memorandum in the role of a Forensic Engineer. This document will be sent to the Court involved with a class action lawsuit that involves the product you will be evaluating. For this purpose, you will address your memorandum to the Judge. However, it must be understandable to the jury who will reference it, and it is also likely to be referenced by the lawyers on both sides of the litigation.
Assignment Reading and Preparation
You will be expected to discuss the elements of this assignment accurately. There are several areas in which students had difficulty in the past that you may want to make sure you are familiar with by doing some additional research
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- Carefully read the problem description; use the Polya method to be sure you consider all the information provided and evaluate how you will analyze the problem. If you feel you need more input on the objects being discussed reference the articles that the assignment images are from or other credible sources.
- Be sure you are clear on the difference between the data you have been provided and your evaluation of it.
- Be sure you understand the difference between negligence and liability. These terms are often used incorrectly (see workshop 6 slides).
- Review class-action lawsuit (Links to an external site.) (Links to an external site.) to be sure you understand what you are dealing with (see workshop 6 slides).
The follow are recommendation and resources that can help you with the assignment, many were used to support workshop 6
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- Find general audience discussions of both hypothesis testing and P-test – seeing these descriptions can help you figure out how to talk about your problem. One excellent source is Medium, an online open publication, among those publishing here are many tech professionals (however, you need to look at their credentials). This site is a subscription service but if you An example of a good option is: do a search with “hypothesis test” and Medium OR ‘p-test’ and medium you should get a number of options you can view for free. One example of a good article is – Everything you Should Know about p-value from Scratch for Data Science by Sharoon Saxena, Senior Machine Learning Engineer at Oracle
For anyone who is interested in additional reading:
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- Validity and reliability of Forensic Engineering Methods and Processes from Forensic Engineering 2006 Proceeding – this resource provides detail on validity and reliability of statistical methods when used in practice.
- Guidelines for Forensic Engineering – this is an e-book that is available from the library. I am linking the two most important chapters – Chapter 1: Introduction, and Chapter 6: The Legal Forum. I believe I will cover the most important information in class, and am providing this more for those of you who want more information.
Problem
In 2022, a wildfire burned more than 10,000 acres in Isley, a small city on the edge of Florida’s Everglades. The fire damaged 89 homes, businesses, and other structures and caused over $42 million in damages. Wildfires require certain environmental conditions to spread, but the initial sparks sometimes come from electrical utility equipment and power lines. An investigation found that the origin of the Isley fire was a transmission tower, where one of the rows of hanging insulators had fallen to the ground. The insulators are designed to protect the tower from the electrical current flowing through the power lines, and they are hung with metal rings, called C-hooks. These C-hooks were manufactured by Seabyrd Iron Works, Inc, who claims that the hooks should not wear more than 5 mm over a fifty-year lifespan. In cooperation with the power company, an independent investigator was hired by the city of Isley to collect data on a random sample of the C-hooks at various transmission towers in the area. It was found that several of the hooks were eroding at a faster rate than was promised by the Seabyrd Iron Works when the local electric company purchased and installed them throughout their electric power system in the 1981.
The local utility company has blamed Seabyrd Iron Works, Inc. for manufacturing sub-standard parts that have worn prematurely. Civil litigation against the manufacturer has ensued, and a class-action lawsuit has been brought forth. In a class-action lawsuit, a certified group of individuals – a group called Isley Homeowners, in this case – sues the defendant for financial damages, claiming that the C-hooks provided in 1981 were not manufactured up to standard. The judge in this case has requested an impartial expert witness, and you have been brought in as a forensic engineer. Forensic engineers investigate the causes of failure in engineering projects ranging from faulty machinery to collapsed buildings. You will analyze the data the independent investigator collected and come to a statistically informed conclusion with a confidence level of 99% on whether the C-hooks used on transmission towers in Isley have already exceeded their promised wear of not more than 5.0 millimeters in 50 years.
The data provided by the independent investigator is below. Because it would be infeasible to test every C-hook in the area, eight transmission towers (labeled in the first column) were randomly selected, and the level of wear on the six C-hooks on each tower was measured. Does this sample data suggest that the average C-hook supplied by Seabyrd Iron Works has passed 5.0 mm in wear?
You will provide your findings in a memorandum addressed to the judge, Tanya Wasilew, and copied to the defense attorney, Mitch Soldano, and the plaintiffs’ attorney Amira Herana. Remember that you are writing to convince the jury.
Technical Input
While the problem statement above is fictional. However, C-hook failures on a transmission tower were the purported cause of the 2018 Camp Fire in California. The utility company settled with a bankruptcy court and agreed to pay $1 billion in damages from several fires in the area. Below are photographs of the C-hook installations to give you information on the object you will be writing about.