• Researchers use the terms variable, subject, sample, and population when describing their research.
• Psychologists do research to measure and describe behavior; to understand when, why, and how events occur; and to apply knowledge to real-world problems.

• Psychologists use the scientific method, which is a standardized way of making observations, gathering data, forming theories, testing predictions, and interpreting results.
• Research must be replicable, falsifiable, precise, and parsimonious.

• Psychologists use descriptive or correlational methods such as case studies, surveys, naturalistic observation, and laboratory observation to describe events, experiences, or behaviors and to look for links between them.
• Researchers use tests to collect information about personality traits, emotional states, aptitudes, interests, abilities, values, or behaviors.
• Tests must be reliable and valid.
• Researchers use experiments to collect information about causal relationships between variables.
• In experiments, researchers include experimental and control groups.
• Bias is the distortion of results by a variable.
• Types of bias include sampling bias, subject bias, and experimenter bias.

• Psychologists must consider ethical norms when doing research involving humans or animals.

• Researchers analyze and interpret the data they’ve collected by using descriptive statistics and organizing their information in histograms or bar graphs.
• Researchers use inferential statistics to determine the likelihood that a result is due simply to chance.
• Statistical significance means that a result is probably not due to chance.