Chapter 1

Introduction to Data

Learning Objectives

• Identify the type of variables (e.g. numerical or categorical; discrete or continuous; ordered or not ordered).
• Identify the relationship between multiple variables (i.e. independent vs. dependent).
• Define variables that are not associated as independent.
• Be able to describe and identify the difference between observational and experimental studies.
• Distinguish between simple random, stratified, and cluster sampling, and recognize the benefits and drawbacks of choosing one sampling scheme over another.
• Identify the four principles of experimental design and recognize their purposes: control any possible con- founders, randomize into treatment and control groups, replicate by using a sufficiently large sample or repeating the experiment, and block any variables that might influence the response.

Supplemental Readings

• OpenIntro Statistics slides

Videos

OpenIntro provides a number of videos. You may find these helpful while reading the chapter.

Case Study: Using Stents to Prevent Strokes

Data Basics: Observations, Variable, and Data Matrices

Data Collection Principles

Observational Studies and Sampling Strategies

Designing Experiments

Using Randomization to Analyze a Gender Discrimination Study