How to avoid bias in scientific tests

00:03:06
https://www.youtube.com/watch?v=BNICMrYtPJY

Resumo

TLDRThe video discusses the significance of bias in scientific investigations, emphasizing its potential to skew results if not identified and eliminated. It illustrates systematic errors, or biases, using various examples. For instance, a faulty thermometer consistently reading five degrees higher demonstrates measurement bias. To avoid such biases, weather services use specially designed sheaths for thermometers. The video further explores selection bias, such as using a non-representative sample in vaccine trials, and confirmation bias, where evidence is selectively interpreted to support a hypothesis. Methods to reduce biases include replacing faulty instruments, ensuring random sampling, and actively seeking evidence that contradicts hypotheses.

Conclusões

  • 🌡 Faulty thermometer illustrates measurement bias.
  • 🌞 Thermometers placed in sunlight exhibit systematic errors.
  • 👨‍🔬 Selection bias arises from non-representative samples.
  • 💉 Vaccine trials need diverse groups to avoid bias.
  • 🔍 Confirmation bias twists evidence to fit expectations.
  • 🎯 Identifying biases ensures fair scientific tests.
  • 📊 Random sampling reduces selection bias.
  • 🧪 Bias can occur at any investigation stage.

Linha do tempo

  • 00:00:00 - 00:03:06

    The text discusses the concept of bias in scientific investigations, using the example of a faulty thermometer that always gives readings five degrees too high, introducing systematic errors, or bias. It emphasizes the importance of eliminating bias to ensure accurate results. Other examples include how external factors can affect thermometer readings, and the concept of measurement bias, which arises from data collection methods. The text also describes selection bias, illustrated by a vaccine test sample that isn't representative of the population, and confirmation bias, where evidence is selectively interpreted to fit a hypothesis. The importance of recognizing and avoiding bias to conduct fair and accurate scientific tests is highlighted.

Mapa mental

Mind Map

Perguntas frequentes

  • What is bias in scientific terms?

    Bias in science refers to a systematic error that affects the accuracy of measurements or judgments.

  • How can a faulty thermometer demonstrate bias?

    A faulty thermometer that always reads five degrees higher represents a systematic error, or bias, that affects temperature readings.

  • What is measurement bias?

    Measurement bias is a systematic error arising from the way data is collected, such as a thermometer being placed in direct sunlight.

  • How can selection bias affect a vaccine trial?

    If a sample in a vaccine trial is not representative of the population, such as using only young healthy males, it can incorrectly skew the results.

  • What is confirmation bias?

    Confirmation bias occurs when evidence is selected or interpreted to fit a preconceived hypothesis, ignoring alternative explanations.

  • How can weather services avoid bias in temperature readings?

    Weather services avoid bias by placing thermometers in specially designed white boxes to prevent external influences.

  • Why is random sampling important?

    Random sampling is important for avoiding selection bias and ensuring the sample represents the target population.

  • How can confirmation bias be mitigated?

    Confirmation bias can be reduced by considering alternative explanations and seeking evidence against the hypothesis.

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  • 00:00:03
    imagine you have a thermometer that
  • 00:00:04
    always gives readings that are five
  • 00:00:06
    degrees higher than the actual
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    temperature
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    every measurement you take with it will
  • 00:00:10
    be wrong
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    because there's a pattern in the way
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    this arrow arises it's systematic
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    rather than random in science any
  • 00:00:19
    systematic error is called a bias
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    to make sure the results of an
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    investigation are as accurate as
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    possible
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    we always need to be on the lookout for
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    biases and try to eliminate them
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    in the case of the faulty thermometer
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    you can simply replace it
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    but other types of bias are harder to
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    identify and avoid
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    for example even an accurate thermometer
  • 00:00:44
    will give the wrong reading
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    if it's placed in direct sunlight or
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    held in your hand
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    to avoid these biases weather services
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    place their thermometers in specially
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    designed white boxes
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    these are examples of measurement bias
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    which is a systematic error that arises
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    because of the way data is collected
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    but there are many other types of bias
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    that can influence an investigation
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    in different ways imagine you're testing
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    a new vaccine to fight a deadly virus
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    you gather a sample of human volunteers
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    from your local university
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    if they all happen to be healthy men in
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    their 20s then this could systematically
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    skew the results
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    maybe the vaccine is less effective in
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    women or has side effects that only
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    appear in older people with heart
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    conditions
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    because your sample is not
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    representative of the wider population
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    your results will be limited at best
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    this type of error is called a selection
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    bias
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    which arises when our sample does not
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    represent the target population
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    one way of avoiding it is through random
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    sampling
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    another common type of bias is even
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    hardest spot
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    imagine you're investigating the
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    hypothesis that artificial
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    food coloring causes hyperactivity in
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    children
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    you set up a test in which one group of
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    children eats brightly colored sweets
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    while a control group eats fresh fruit
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    sure enough the children who ate the
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    sweets with food coloring are soon
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    bouncing off the walls
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    your hypothesis is being confirmed
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    but you fail to take into account
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    alternative explanations for the result
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    such as the higher sugar content of
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    sweets compared to the fruit the
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    systematic error that arises when we
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    select or interpret evidence
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    to fit our hypothesis is called
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    confirmation bias
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    we can avoid this by always considering
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    alternative explanations
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    and actively seeking evidence against
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    our hypothesis
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    to sum up biases can arise at any stage
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    of an investigation
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    from designing the method and collecting
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    data to interpreting the results and
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    drawing conclusions
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    they can be produced by measuring
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    instruments sampling methods
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    or an unconscious desire to be proved
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    correct
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    so to make sure you design a fair test
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    try to identify and avoid
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    all sources of bias
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    you
Etiquetas
  • bias
  • systematic error
  • measurement bias
  • selection bias
  • confirmation bias
  • random sampling
  • scientific investigation