9/14/2009
Comments on Minute Card
- Extrapolation - Using the least squares line for prediction outside the range of data used to compute the least squares line.
- Pace of the course
- Textbook: expectations regarding reading assignments
Regression Activities
- Anscombe's Data (p:\data\math\stats\Anscombe.mtw)
- Nonlinear Regression (p:\data\math\stats\alligator.mtw)
Association versus Causation
- Polio Vaccine
- Before the introduction of the Salk vaccine, investigators
looked at the relationship between the incidence of polio and the number of
soft drinks sold. A strong positive correlation between the number of
soft drinks sold per week and the number of new cases of polio reported was
detected. What does this tell you?
- Establishing Cause and Effect Relationships
- The best method of establishing causation is to
conduct a carefully designed experiment in which the effects of possible lurking
variables are controlled.
Step-by-Step Process for Planning an Experiment
- Identify your objective.
- Decide what information to collect.
- Decide how to collect the information.
- Decide how many experimental units are needed.
- Use randomization to assign experimental units to treatments.
- Collect the data.
- Analyze the data.
Gummi Bear Experiments