BIO 105 Home
Questions | Answers

1. A way of knowing about the natural world using a process designed to reduce the chance of being misled.

2. Process:

  • Observation
    • Go see your neighbor's fish pond to confirm the fish died.
  • Question
    • Ask, "Why have my neighbor's fish died in the pond?"
  • Literature Review
    • Read the literature to find out the survival requirements for the fish that were in your neighbor's pond.
  • Multiple Hypotheses
    • Come up with as many possible answers to the question as you can.
      • The fish died because the water was too hot.
      • The fish died because there was not enough oxygen.
  • Deductions
    • If the fish died because the water was too hot, then the water temperature would have to be above 90 degrees.
  • Tests
    • Measure the water temperature in the pond. I found out it was 94 degrees.
  • Tentative Conclusions
    • My neighbor's fish died because the water temperature was too hot.
  • Peer Review
    • I would submit my report to a scientific journal.

3. Rules

  • Maximize Sample Size
    • Collect data from as large a sample as possibl (1000+).
      • Example: if you want to know the average height of PCC students, you can't just measure the height of 10 students, measure the height of 1000s.
  • Representative Sample
    • Choose the sample you are going to study randomly or systematically to avoid bias.
      • Example: if you want to know the average height of PCC students, you can't just measure the height of all the basketball players, you need to measure the height of students representing as much of the variability as possible. You also can't measure just the height of middle school students..
  • Controlled Studies
    • Always have a control group to compare to the experimental group and always have just one variable be different between the control group and the experimental group at a time so you can be more sure that any effects seen in the experimental group that are not seen in the control group likely arose from that particular cause.

4. Dependent variable, independent variable

  • Example: Is there a difference in human health at different concentrations of air pollution? What are the dependent and independent variables?
    • Dependent Variable: human health
    • Independent Variable: concentration of air pollution