心理统计学（全套课件）.pdf

心理统计学 1 Chapter 1: Introduction to Statistics 2 Variables • A variable is a characteristic or condition that can change or take on different values. • Most research begins with a general question about the relationship between two variables for a specific group of individuals. 3 Population • The entire group of individuals is called the p。pulati。n. • For example, a researcher may be interested in the relation between class size (variable 1) and academic performance (variable 2) for the population of third-grade children. 4 Sample • Usually populations are so large that a researcher cannot examine the entire group. Therefore, a sample is selected to represent the population in a research study. The goal is to use the results obtained from the sample to help answer questions about the population. 5 THE POPULATION All of the individuals of in↑eres↑ The resul↑s The sample from ↑he so 门1 ple is selec↑ed from are generalized ↑he popula↑ion ↑0↑he popula↑ion THE SAMPLE The individuals selec↑ed ↑o par↑icipa↑e in ↑he research s↑udy Types of Variables • Variables can