CH1 Scientific Inquiry

• table columns


  column 1 = independent variable

  column 2 = dependent variable
• When is a line graph used?

  continuous data
• when is a histogram used?

  frequencies
• when is a bar/column graph used?

  discrete data
• independent variable


  factor being investigated and deliberately changed
• dependent variable


  factor being measured and changed due to changes in the independent variable
• hypothesis


  must be directional: an increase In x causes a decrease in y
• What makes an investigation valid?

  changes in the dependent variable are only due to changes in the independent variable
• What makes an investigation reliable?


  By performing multiple trials and receiving the same results, increasing sample size and repeating the experiment on a different day.
• How is accuracy achieved?

  Achieved if correct measuring equipment is used
• Analysis & Evaluation answers


  describe trends/patterns with numerical evidence

  provide reason for these trends/patterns (content)

  does the data approve or disprove the hypothesis?

  list 2 improvements

  list 2 limitations affecting reliability
• Placebo


  something which has a positive mental effect, but no physical effect
• systematic error


  faulty equipment: change equipment or procedure
• random error


  occurs due to the fact that measurements aren't always precise: take multiple measurements and calculate the average
• Human error


  1. incorrectly reading scale on an instrument

  2. spilling liquid before measuring the volume

  3. calculation mistake
• voluntary participation


  no pressure in taking part
• informed consent


  be told enough to enable them to choose whether they wish to participate
• risk of harm


  minimise any risks present
• confidentiality


  identity isn't revealed unless its to those directly involved
• anonymity


  stronger privacy guaranteeing the identity o the person isn't revealed, even to the researchers.
• why the mean can be misleading


  it can be influenced by outliers. giving a false impression of the central tendency of the data.
• why is a placebo used

  to provide a control

  allow comparisons of the dependent variable with no independent variable is used

  to enable the effect of the independent variable onto the dependent variable
• 3 controlled variables to ensure a fair trial


  Both groups are of similar age

  Both groups are of similar health

  Both groups are of similar size/stature