### Objectives: Learning objectives

- Distinguish between the population and a sample and between the parameter and a statistic.
- Know when to summarize a data set using a mean versus a proportion.
- Understand why anecdotal evidence is unreliable.
- Identify the four main types of data collection: census, sample survey, experiment, and observation study.
- Classify a study as observational or experimental, and determine when a study’s results can be generalized to the population and when a causal relationship can be drawn.