Sources: PowerPoint

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 friend's fish pond to confirm the absence of fish, etc.
• 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 and to find out about past reasons fish have died in ponds.
• Multiple Hypotheses
  • Come up with as many possible answers to the question as you can.
    • The water was not the right temperature, there was not enough oxygen, there was not enough food, over-harvesting by you neighbor or predators, toxins, etc.
• Deductions
  • For each hypothesis, determine what evidence (data) would be required to refute the hypothesis or support the hypothesis.
    • Example: The water temperature must be below 40 degrees or above 90 degrees to kill the fish.
• Tests
  • Collect the actual data
    • Example: The water temperature in the pond always is between 71 and 82 degrees.
• Tentative Conclusions
  • Report your methods and results and state which hypotheses seem to be supported and which you were able to rule out tentatively.
    • Example: Water temperature most likely was not the cause of the fish dieoff.
• Peer Review
  • Submit your report to a scientific journal. The journal editors give your report to scientists who critique the scientific soundness and merits of your report.

3. Rules

• Maximize Sample Size
  • Collect data from as large a sample as possible and needed based on the population's variability and the amount of certainty required.
    • Example: if you want to know the average height of PCC students, you can't just measure the height of 10 students.
• 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.
• Controlled Studies
  • Use when determining the cause of an effect.
    • 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.