Experimental and Sampling Design, Ethics
The Question of Causation
Learning goals for this chapter:
Identify unit/subject, sample, population, treatment, factors and levels, and response variable
from a story.
Recognize whether a story is an experiment, observational study, or anecdotal evidence.
Explain the difference between population and sample and between taking a census and
Decide the correct type of sampling used in a story and explain the benefits/drawbacks of
each: voluntary response, simple random sample (SRS), stratified random sample, multistage
random sample, catch and release sample.
Explain and identify sources of sampling bias: undercoverage, nonresponse, response bias.
Discuss sampling variability and bias and how to reduce them.
Understand the difference between a parameter and a statistic.
Explain what a sampling distribution is.
Know the 3 principles of experimental design: randomization, replication, and control group.
Talk about lurking variables, placebos, control groups, the placebo effect, and double-blind
experiments in context.
Identify and outline the specific type of experimental design in a story: completely
randomized, randomized block, matched pairs.
Use SPSS for random selection (sampling) or assignment (experiment).
Know the difference between causation, confounding, and common response when applied to
a specific story.
Explain the ethics of experimental design with humans (in context): review board, informed
consent, individual data kept confidential.
Explain the ethics of experimental design with animals (in context): replacement, reduction,
refinement (3 Rs).