Data Collection and Bias

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Data Collection and Bias
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Whats the problem?

• A student hands out a one-page questionnaire to
  every student to find out the most popular
  extracurricular activities.
• Use a sample instead of a population
• A questionnaire reads What is your favourite
  type of meat?
• Give examples

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• 3) A survey asks Have you ever told a lie?
• Choose a less personal subject
• 4) A survey asks What is the best job?
• Have more clear and focused questions
• 5) A survey asks How do you feel about
  recycling in school?
• Very general, replace with questions that will
  result in data that can be organized

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• First-hand data
• Data collected by the person using it
• Data from a survey is first-hand data
• Second-hand data
• Data collected by someone other than the person
  using it
• An encyclopedia and the Internet are examples of
  second-hand data sources

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In your notebook

• Explain how you could find data to answer
• each question. Would you be using first- or
• second-hand data?
• Your familys favourite restaurant.
• Medal standings for the Olympics.
• The number of snowshoe hares in Nova Scotia.

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• Bias
• The wording of the question that encourages a
  certain response
• Ex. Do you agree that all schools should have a
  cafeteria?

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Bias in Survey Questions

• Read each question. Decide
• whether or not it contains
• bias. If there is bias, explain
• how it could be removed.

• 1) What is your favourite sport?
• A Hockey B Golf
• C Baseball D Other _____

• 2) Should schools adopt a
• more reasonable schedule
• by changing to a four-day
• week?

• 3) Do you think professional
• athletes are paid too much,
• about right, or too little?

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Classwork

• Pages 260-261
• 1, 3, 4, 6 - 9