1b. Experimental Design

Blind study: study where experimenter knows, but participants don’t know

Double Blind study: study where experimenters and participants don’t know

Triple Blind study: study where experimenters, participants, and data analyzers don’t know

Confounding factors: cause two measured variables to falsely appear to be in a causal relationship

Scientific Method in Ecology

  • field is benchmark, why? bc controlled
  • anything that happens in the lab may not be whats happening in the field

Two types of Science

Discovery

  • involves detailed description of a biological phenomenon
  • can also involve serendipitous discoveries
    • ex penicillin
  • leads to further questions that can be tested with the scientific method
  1. detailed observations of natural world
  2. with these, meaningful questions about how the system works can be formulated
  3. predictions use “if… then” logic
  4. test those predictions by performing experiments to see whether or not results are as predicted, and thus support the hypothesis
  • history of experimental design
    • started with cup of tea
  • when designing manipulative experiments, important to use controlled experiments
    • treatment groups and control groups
    • focuses on a single variable
    • without control, no way to tell if other factors impact the environment
    • must be replication or else the results aren’t due to chance
    • groups assigned randomly
  • experimental fundamentals: randomize, replicate, control
  • potential problems:
    • manipulative/observational
    • sufficient sample size
    • model, lab, or field
    • any confounding factors

Hypothetico-deductive