Random Selection

Definition

Random selection defines the selection of participants for a study at random, drawn from a predefined total population of participants.

Introduction

Statistical inference is based on the theory of probability, and effects investigated in psychological studies are defined by measures that are treated as random variables. The only way to ensure that these distributions provide correct information that can be used for statistical inference is random selection of the observations (usually participants of the study) from a predefined population of total observations. The inference about the probability of a given result with regard to an assumed population and the popular term “significance” are only meaningful and without bias if the measure of interest is really a random variable. To achieve the creation of a random variable in form of a measure derived from a sample of participants, these participants have to be drawn at random.

Random Variables

Random variables are functions...