Science Appendix

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Science Appendix

• The Nature of Scientific Research

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Science Is A Way of Knowing

• The process of research can involve several
  steps. These levels are summarized below, and
  often they progress in the sequence shown

• OBSERVATION What is happening?
• QUESTION What would happen if .....?
• HYPOTHESIS ________ should happen if....
• ALTERNATIVE HYPOTHESES _________or _________ or
  _________ should happen if .....

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Good Research Is Hypothesis-Driven

• Why is this true?
• Hypotheses guide orderly thought, experimental
  design, and provide a framework for interpreting
  data.

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So Whats A Hypothesis?It ranges from an
educated guess to an inspired insight.

• Based on something you think you know
• Can be a logical conclusion (deduction)
• Can be a creative synthesis (induction)
• Should be testable
• Experimental design should predict certain results

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Hypothesis Example

• Fact We know that lead is a poison.
• Hypothesis Other heavy metals might be toxic.
• Test Expose one group of experimental animals to
  lead, another to cadmium, another to uranium,
  etc.
• Prediction One or more of the metals will prove
  to be toxic.

Click here to learn about periodic table of
elements
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Testing HypothesesAccount for the Variables

• Variables are factors or conditions that could
  influence the results.
• Need to hold all variables constant except the
  one being tested.
• Need for a control for variable under test.
• Methods used must be appropriate - and sensitive
  - for the variable under test.
• Must consider alternative explanations for the
  results.

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• EXPERIMENTAL DESIGN How do we test and control
  what happens in our experiments so the results
  can be trusted?
• EXPERIMENT Lets find out what happens when we
  conduct the tests.
• INTERPRETATION What is the meaning of what
  happened?

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Example for the Metal Variables

• Keeping variables constant Each group exposed to
  only one metal.
• Control One group tested exactly as the others,
  but without any metal exposure.

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Metal Variables - Test Method -

• Identify appropriate test species.
• Identify appropriate indicators of sickness and
  how they could be measured.
• Test a meaningful range of doses over appropriate
  time of exposure.

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Metal Variables - Alternative Explanations -

• Results could be false negative or false
  positive.
• Possible causes for misleading results
• 1. Species may be insensitive or too sensitive.
• 2. Route of exposure may not be appropriate.
• 3. Dose may not be equivalent to human dose.
• 4. Time of exposure may be too short or too
  long.
• 5. Some signs of sickness may not have been
  tested.
• 6. Too few test subjects could create
  statistical error.

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Consequences of Scientific Evidence

• EVIDENCE-BASED DECISIONS What do we want to make
  happen as a result of the evidence?
• VALUES What happenings do we want to preserve
  and extend?
• FUTURE DIRECTIONS What do we want to make happen
  next? Where will these results lead us in the
  future?

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Common Interpretation Errors

• Assuming that if two events are correlated, one
  must be causing the other.
• Failure to consider alternative explanations.
• Extending conclusions beyond what is supported by
  the data.