Lesson 2: Defining Basic Terms
This section presents definitions of basic . Later chapters will define these terms in a formal way.
What is statistics?
One of the many definitions of statistics is conceived as the systematic set of procedures for the observation, registration, organization, synthesis and analysis and interpretation of phenomena and the laws that regulate them in order to predict or conclude about them. This definition clearly involves the two phases of statistics: descriptive and inferential.
Descriptive statistics
It is the phase of description, organization, synthesis and analysis of the information of interest but without reaching strong or deep conclusions about it; moreover, a phase of collecting and organizing information for careful examination.
inferential statistics
This phase seeks to obtain solid and deeper conclusions than a simple description of the information, based on the work with samples and their subsequent generalization of results for decision making and solid conclusions.
Population
The POPULATION, is the set of measurements obtained by observing some characteristic of interest in the elements of the collective, which indicates that several populations can, in general, be associated with the same collective.
Variable
VARIABLE is an observable characteristic in an object of study, which can take different values.
QUALITATIVE variables are those whose elements are of a qualitative nature, not susceptible to numerically measurable observation.
QUANTITATIVE variables such as those whose properties can be presented in various degrees or intensities of a numerical nature.
According to their mathematical nature, quantitative variables are differentiated into DISCRETE AND CONTINUOUS, the former being those that are defined over finite or infinitely countable paths; they cannot take intermediate values between two given values. The continuums are those defined over uncountable infinite paths; they can take any value within a given range.
Measurement Scales
Para clasificar las variables se utilizan diferentes tipos de escalas, siendo las mas comunes las NOMINALES, las ORDINALES, las DE INTERVALO, y las DE RAZON, cuyo uso depende básicamente de los objetivos del estudio y de la naturaleza de la variable.