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The ‘average’ revolutionized scientific research, but overreliance on it has led to discrimination and injury

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The ‘average' revolutionized scientific research, but overreliance on it has led to discrimination and injury

The average can tell you a lot about a dataset, but not everything.
marekuliasz/iStock via Getty Images Plus

Zachary del Rosario, Olin College of Engineering

When analyzing a set of data, one of the first steps many people take is to compute an average. You might compare your height against the average height of people where you , or brag about your favorite player's batting average. But while the average can you study a dataset, it has important limitations.

Uses of the average that ignore these limitations have led to serious issues, such as discrimination, injury and even life-threatening accidents.

For example, the U.S. Force used to design its planes for “the average man,” but abandoned the practice when pilots couldn't control their aircraft. The average has many uses, but it doesn't tell you anything about the variability in a dataset.

I am a discipline-specific education researcher, meaning I study how people learn, with a focus on engineering. My research includes study of how engineers use averages in their work.

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Using the average to summarize data

The average has been around for a long time, with its use documented as early as the ninth or eighth century BCE. In an early instance, the Greek poet Homer estimated the number of soldiers on ships by taking an average.

Early astronomers wanted to predict future locations of stars. But to make these predictions, they first needed accurate measurements of the stars' current positions. Multiple astronomers would take position measurements independently, but they often arrived at different values. Since a star has just one true position, these discrepancies were a problem.

Galileo in 1632 was the first to push for a systematic approach to address these measurement differences. His analysis was the beginning of error theory. Error theory helps scientists reduce uncertainty in their measurements.

Error theory and the average

Under error theory, researchers interpret a set of measurements as falling around a true value that is corrupted by error. In astronomy, a star has a true location, but early astronomers may have had unsteady hands, blurry telescope images and bad weather – all sources of error.

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To deal with error, researchers often assume that measurements are unbiased. In statistics, this means they evenly distribute around a central value. Unbiased measurements still have error, but they can be combined to better estimate the true value.

Say three scientists have each taken three measurements. Viewed separately, their measurements may seem random, but when unbiased measurements are put together, they evenly distribute around a middle value: the average.

When measurements are unbiased, the average will tend to sit in the middle of all measurements. In fact, we can show mathematically that the average is closest to all possible measurements. For this reason, the average is an excellent tool for dealing with measurement errors.

Statistical thinking

Error theory was, in its time, considered revolutionary. Other scientists admired the precision of astronomy and sought to bring the same approach to their disciplines. The 19th century scientist Adolphe Quetelet applied ideas from error theory to study humans and introduced the idea of taking averages of human heights and weights.

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The average helps make comparisons across groups. For instance, taking averages from a dataset of male and female heights can show that the males in the dataset are taller – on average – than the females. However, the average does not tell us everything. In the same dataset, we could likely find individual females who are taller than individual males.

So, you can't consider only the average. You should also consider the spread of values by thinking statistically. Statistical thinking is defined as thinking carefully about variation – or the tendency of measured values to be different.

For example, different astronomers taking measurements of the same star and recording different positions is one example of variation. The astronomers had to think carefully about where their variation came from. Since a star has one true position, they could safely assume their variation was due to error.

Taking the average of measurements makes sense when variation comes from sources of error. But researchers have to be careful when interpreting the average when there is real variation. For instance, in the height example, individual females can be taller than individual males, even if are taller on average. Focusing on the average alone neglects variation, which has caused serious issues.

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Quetelet did not just take the practice of computing averages from error theory. He also took the assumption of a single true value. He elevated an ideal of “the average man” and suggested that human variability was fundamentally error – that is, not ideal. To Quetelet, there's something wrong with you if you're not exactly average height.

Researchers who study social norms note that Quetelet's ideas about “the average man” contributed the modern meaning of the word “normal” – normal height, as well as normal behavior.

These ideas have been used by some, such as early statisticians, to divide populations in two: people who are in some way superior and those who are inferior.

For instance, the eugenics movement – a despicable effort to prevent “inferior” people from traces its thinking to these ideas about “normal” people.

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While Quetelet's idea of variation as error supports practices of discrimination, Quetelet-like uses of the average also have direct connections to modern engineering failures.

Failures of the average

In the 1950s, the U.S. Air Force designed its aircraft for “the average man.” It assumed that a plane designed for an average height, average arm length and the average along several other key dimensions would work for most pilots.

This contributed to as many as 17 pilots crashing in a single day. While “the average man” could operate the aircraft perfectly, real variation got in the way. A shorter pilot would have trouble seeing, while a pilot with longer arms and legs would have to squish themselves to fit.

While the Air Force assumed most of its pilots would be close to average along all key dimensions, it found that out of 4,063 pilots, zero were average.

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The Air Force solved the problem by designing for variation – it designed adjustable seats to account for the real variation among pilots.

While adjustable seats might seem obvious now, this “average man” thinking still causes problems . In the U.S., women experience about 50% higher odds of severe injury in automobile accidents.

The Accountability Office blames this disparity on crash-test practices, where female passengers are crudely represented using a scaled version of a male dummy, much like the Air Force's “average man.” The first female crash-test dummy was introduced in 2022 and has yet to be adopted in the U.S.

The average is useful, but it has limitations. For estimating true values or making comparisons across groups, the average is powerful. However, for individuals who exhibit real variability, the average simply doesn't mean that much.The Conversation

Zachary del Rosario, Assistant Professor of Engineering, Olin College of Engineering

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This article is republished from The Conversation under a Creative Commons license. Read the original article.

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The Conversation

Under the influence and under arrest − what happens if you’re drunk in the interrogation room?

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theconversation.com – Jacqueline R. Evans, Associate Professor of Psychology, Florida International – 2024-04-26 07:28:33

In the U.S., if you waive your Miranda rights, you'll be interrogated – whether you're drunk or sober.

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Jacqueline R. Evans, Florida International University

Imagine it's Friday night. You're enjoying happy hour with friends after a long . You're relaxed, indulged in several of your preferred adult beverages. Now imagine that as you the bar, a officer approaches. You're under arrest.

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Flash forward to the police station. The officer takes you to a cramped room and reads you your Miranda rights: You have the right to remain silent, to an attorney, and all the rest. Let's say you waive those rightsmost people do – and the officer questions you for several hours.

While under the influence, would you understand your Miranda rights and appreciate the consequences of choosing to invoke or waive them? Would the statements you made during questioning be more or less reliable than how you'd respond sober? Would a jury take what the drunken you said seriously? These are the questions that legal psychologists like me and my colleagues seek to address in our research.

Suspects get similar treatment, drunk or not

When we've surveyed police, they revealed it's common to question intoxicated suspects and that they tend to use the same interrogation techniques with drunken suspects that they normally use. Surveys of community members about their experience with interrogation confirm that questioning drunken suspects is common. In fact, sometimes police even interrogate drunken juveniles.

Of course, police in the U.S. cannot legally question anyone in custody unless that person has waived their Miranda rights and chosen to to the investigator. It's a common misperception that drunken people cannot legally waive their Miranda rights and that statements given while intoxicated cannot be used against them in court. But the reality is that from a legal perspective the police can Mirandize you while you're under the influence, interrogate you, and use your statements against you.

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arrow upwards with text describing expected impairments at increasing BAC levels

Level of impairment rises along with how much you've had to drink.

NIH National Institute on Alcohol Abuse and Alcoholism, CC BY

Consider the case of Travis Jewell. When he was arrested for fleeing a police officer in his truck, his blood alcohol level was .29, more than three times the legal limit of .08 in the U.S. The interrogator reported Jewell was slurring words and struggling to stand. Nonetheless, the court accepted his Miranda waiver, making Jewell's statements admissible during trial.

While Miranda waivers from intoxicated people may be legally valid, research from my lab suggests that when with sober individuals, someone under the influence of or alcohol – even at low levels of intoxication – may be less able to comprehend their rights.

Testing how drunken ‘suspects' behave

Critically, researchers know almost nothing about how intoxicated people behave during interrogation.

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To address this need, my colleagues and I brought university student volunteers into the lab, where we have safeguards in place to minimize risks. We had some of our participants drink enough vodka to reach a breath alcohol level of .08%, a level consistent with the legal driving limit in the U.S.

Then we set the participants up to be guilty or innocent of cheating, and interrogated each of them about potential academic misconduct. We were interested in whether, impaired or sober, they said anything incriminating or suspicious during questioning.

About two-thirds of sober participants said something suggestive of guilt, while even more intoxicated participants did. The difference in suspicious statements between the groups was not statistically significant, but our findings do indicate that intoxicated people – just like the rest of the public – are at a high risk of self-incrimination. And remember, in our study, half of the participants were innocent of the infraction they were being questioned about.

man in striped clothes sits across table from woman in suit jacket

Standard legal advice is to keep your mouth shut until you are able to meet with a lawyer.

AP Photo/Steve Helber

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Suspicious remarks can have immediate consequences during interrogation. When a says something suggestive of guilt, it tends to increase an interrogator's belief that they're guilty. When interrogators have a stronger belief in guilt, they then tend to be more accusatory, an approach associated with false confessions.

Intoxicated suspects – guilty or innocent – are very likely to make a guilt-suggestive statement, which in turn is likely to invite more coercive interrogation approaches. This could potentially explain our recent real-world findings in Sweden that police interrogators used more confrontational techniques with intoxicated suspects than with sober suspects.

On a positive note, our work has also shown that potential jurors seem to recognize that intoxication may lead to less reliable statements during interrogation. They tend to give less weight to a confession from an intoxicated suspect than from a sober suspect. While that may sound reassuring, should you find yourself in that cramped interrogation room, sober or intoxicated, exercise your rights and ask for an attorney.The Conversation

Jacqueline R. Evans, Associate Professor of Psychology, Florida International University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

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Cybersecurity researchers spotlight a new ransomware threat – be careful where you upload files

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theconversation.com – Selcuk Uluagac, Professor of Computing and Information Science, Florida International – 2024-04-26 07:28:18

Avoiding iffy downloads is no longer enough to ensure this doesn't happen.

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Selcuk Uluagac, Florida International University

You probably know better than to click on links that download unknown files onto your computer. It turns out that uploading files can get you into trouble, too.

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Today's web browsers are much more powerful than earlier generations of browsers. They're able to manipulate data within both the browser and the computer's local file system. Users can send and receive email, listen to music or watch a within a browser with the click of a button.

Unfortunately, these capabilities also mean that hackers can find clever ways to abuse the browsers to trick you into letting ransomware lock up your files when you think that you're simply doing your usual tasks online.

I'm a computer scientist who studies cybersecurity. My colleagues and I have shown how hackers can gain access to your computer's files via the File System Access Application Programming Interface (API), which enables web applications in modern browsers to interact with the users' local file .

The threat applies to Google's Chrome and Microsoft's Edge browsers but not Apple's Safari or Mozilla's Firefox. Chrome accounts for 65% of browsers used, and Edge accounts for 5%. To the best of my knowledge, there have been no reports of hackers using this method so far.

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My colleagues, who include a Google security researcher, and I have communicated with the developers responsible for the File System Access API, and they have expressed support for our work and interest in our approaches to defending against this kind of attack. We also filed a security report to Microsoft but have not heard from them.

Double-edged sword

Today's browsers are almost operating systems unto themselves. They can software programs and encrypt files. These capabilities, combined with the browser's access to the host computer's files – including ones in the cloud, shared folders and external drives – via the File System Access API creates a new for ransomware.

Imagine you want to edit photos on a benign-looking online editing tool. When you upload the photos for editing, any hackers who control the malicious editing tool can access the files on your computer via your browser. The hackers would gain access to the folder you are uploading from and all subfolders. Then the hackers could encrypt the files in your file system and demand a ransom payment to decrypt them.

Today's web browsers are more powerful – and in some ways more vulnerable – than their predecessors.

Ransomware is a growing problem. Attacks have hit individuals as well as , including Fortune 500 companies, banks, cloud service providers, cruise operators, threat-monitoring services, chip manufacturers, governments, medical centers and hospitals, insurance companies, schools, universities and even departments. In 2023, organizations paid more than US$1.1 billion in ransomware payments to attackers, and 19 ransomware attacks targeted organizations every second.

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It is no wonder ransomware is the No. 1 arms race today between hackers and security specialists. Traditional ransomware runs on your computer after hackers have tricked you into downloading it.

New defenses for a new threat

A team of researchers I at the Cyber-Physical Systems Security Lab at Florida International University, including postdoctoral researcher Abbas Acar and Ph.D. candidate Harun Oz, in collaboration with Google Senior Research Scientist Güliz Seray Tuncay, have been investigating this new type of potential ransomware for the past two years. Specifically, we have been exploring how powerful modern web browsers have become and how they can be weaponized by hackers to create novel forms of ransomware.

In our paper, RøB: Ransomware over Modern Web Browsers, which was presented at the USENIX Security Symposium in August 2023, we showed how this emerging ransomware strain is easy to design and how damaging it can be. In particular, we designed and implemented the first browser-based ransomware called RøB and analyzed its use with browsers running on three different major operating systems – Windows, Linux and MacOS – five cloud providers and five antivirus products.

Our evaluations showed that RøB is capable of encrypting numerous types of files. Because RøB runs within the browser, there are no malicious payloads for a traditional antivirus program to catch. This means existing ransomware detection systems face several issues against this powerful browser-based ransomware.

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We proposed three different defense approaches to mitigate this new ransomware type. These approaches operate at different levels – browser, file system and user – and complement one another.

The first approach temporarily halts a web application – a program that runs in the browser – in order to detect encrypted user files. The second approach monitors the activity of the web application on the user's computer to identify ransomware-like patterns. The third approach introduces a new permission dialog box to inform users about the risks and implications associated with allowing web applications to access their computer's file system.

When it comes to protecting your computer, be careful about where you upload as well as download files. Your uploads could be giving hackers an “in” to your computer.The Conversation

Selcuk Uluagac, Professor of Computing and Information Science, Florida International University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

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How bird flu virus fragments get into milk sold in stores, and what the spread of H5N1 in cows means for the dairy industry and milk drinkers

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theconversation.com – Noelia Silva del Rio, Associate Specialist in Cooperative Extension, Production Medicine and Food Safety, of California, Davis – 2024-04-25 14:04:50

Cows typically get over avian flu in a couple of weeks, but it's an economic blow for farms.

AP Photo/Charlie Litchfield

Noelia Silva del Rio, University of California, Davis; Richard V. Pereira, University of California, Davis; Robert B. Moeller, University of California, Davis; Terry W. Lehenbauer, University of California, Davis, and Todd Cornish, University of California, Davis

The discovery of viral fragments of avian flu virus in milk sold in U.S. stores suggests that the H5N1 virus may be more widespread in U.S. dairy cattle than previously realized.

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The Food and Drug Administration was quick to stress on April 24, 2024, that it believes the commercial milk supply is safe. However, highly pathogenic avian influenza virus can make cows sick, and the flu virus's presence in herds in several states and now new federal restrictions on the movement of dairy cows between states are putting economic pressure on farmers.

Five experts in infectious diseases in cattle from the University of California, Davis – Noelia Silva del Rio, Terry Lehenbauer, Richard Pereira, Robert Moeller and Todd Cornish – explain what the test results mean, how bird flu can spread to cattle and the impact on the industry.

What are viral fragments of avian flu, and can they pose risks to people?

It's crucial to understand that the presence of viral fragments of H5N1 doesn't indicate the presence of intact virus particles that could cause disease.

The commercial milk supply maintains safety through two critical measures:

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  • First, milk sourced from sick animals is promptly diverted or disposed of, ensuring it does not enter the food chain.

  • Second, all milk at grocery stores is heat treated to reduce pathogen load to safe levels, mainly by pasteurization. Pasteurization has been shown to effectively inactivate H5N1 in eggs, and that occurs at a lower temperature than is used for milk.

The viral fragments were detected using quantitative polymerase chain reaction testing, which is known for its exceptional sensitivity in detecting even trace amounts of viral genetic material. These fragments are only evidence that the virus was present in the milk. They aren't evidence that the virus is biologically active.

To evaluate whether the presence of the viral fragments corresponds to a virus with the capacity to replicate and cause disease, a different testing approach is necessary. Tests such as embryonated egg viability studies allow scientists to assess the virus's ability to replicate by injecting a sample into an embryonated chicken egg. That type of testing is underway.

On April 24, 2024, the FDA said it had found no reason to change its assessment that the U.S. milk supply is safe. The agency does strongly advise against consuming raw milk and products derived from it because of its inherent risks of contamination with harmful pathogens, including avian flu viruses.

How does an avian flu virus get into cow's milk?

Currently, cows confirmed to have H5N1 have different symptoms than the typical flu-like symptoms observed in birds.

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Abnormal milk and mastitis, an inflammatory response to infection, are common. While there is speculation that other bodily secretions, such as saliva, respiratory fluids, urine or feces, may also harbor the virus, that has yet to be confirmed.

The legs of a cow showing a milking device attached to the udder and tubes for the milk to flow.

Milking equipment can viruses spread.

Loic Venance/AFP via Getty Images

How waterfowl or other birds transmitted H5N1 to cattle is still under investigation. In 2015, an outbreak of highly pathogenic avian influenza in commercial poultry farms reached its peak in April and May, the same time birds migrated north. Birds can shed the virus through their oral, nasal, urine and fecal secretions. So the virus could potentially be transmitted through direct contact, ingesting contaminated feed or , or inhaling the virus.

Infected dairy cows can shed the virus in milk, and they likely can transmit it to other cows, but that still needs to be proven.

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Contagious pathogens that cause mastitis can be transmitted through milking equipment or contaminated milker's gloves. Ongoing research will help determine whether this is also a potential transmission route for H5N1, and if so, what makes the virus thrive on mammary tissue.

If H5N1 is found to be widespread in milk, what risks can that pose for the dairy industry?

For the dairy industry, infection of cattle with H5N1 avian influenza virus creates challenges at two levels.

The overriding concern is always for the safety and healthfulness of milk and dairy products.

Existing and federal regulations and industry practices require sick cows or cows with abnormal milk to be segregated so that their milk does not enter the food supply. Proper pasteurization should kill the virus so that it cannot cause infection.

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The American Association of Bovine Practitioners has also developed biosecurity guidelines for H5N1, focusing on key practices. These include minimizing wild birds' contact with cattle and their , managing the movement of cattle between farms, isolating affected animals, avoiding feeding unpasteurized (raw) colostrum or milk to calves and other mammals, and ensuring the use of protective personal equipment for animal caretakers.

The other major concern is for the of the dairy herd and the people who take care of the dairy cattle. A farm worker who handled dairy cows contracted H5N1 in in March 2024, but such cases are rare.

No vaccines or specific therapies are available for avian influenza infections in dairy cattle. But good sanitation and biosecurity practices for both people and cows will help to reduce risk of exposure and spread of the avian influenza virus among dairy cattle.

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For cows that get the virus, providing supportive care, including fluids and fever reducers as needed, can help them get through the illness, which can also cause loss of appetite and affect their milk production.

Dairy farms facing an outbreak will have economic losses from caring for sick animals and the temporary reduction in milk sales. Approximately 5% to 20% of the animals in the affected herds have become ill, according to early estimates. Affected animals typically recover within 10 to 20 days.

At least 21 states have restricted importing dairy cattle to prevent the virus's spread, and the federal government announced it will require that lactating dairy cattle be tested before they can be moved between states starting April 29, 2024. While the overall impact on U.S. milk production is projected to be minor on an annual basis, it could to short-lived supply disruptions.

How worried should people be about avian flu?

The federal government's monitoring and food safety measures, along with pasteurization, provide important safeguards to protect the public from potential exposure to avian influenza virus through the food chain.

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Drinking raw milk, however, does represent a risk for exposure to multiple diseases, including H5N1. This is why the FDA and Centers for Disease Control and Prevention strongly recommend drinking only pasteurized milk and dairy products.The Conversation

Noelia Silva del Rio, Associate Specialist in Cooperative Extension, Production Medicine and Food Safety, University of California, Davis; Richard V. Pereira, Associate Professor of Veterinary Medicine and Associate Agronomist, University of California, Davis; Robert B. Moeller, Professor of Veterinary Medicine, University of California, Davis; Terry W. Lehenbauer, Professor of Veterinary Medicine, University of California, Davis, and Todd Cornish, Professor of Veterinary Medicine, University of California, Davis

This article is republished from The Conversation under a Creative Commons license. Read the original article.

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