Research Methodologies and Statistical Fundamentals

Types of Research

Descriptive and Explanatory Research

Descriptive Research: Aims to show a situation or phenomenon.

Explanatory Research: Seeks to uncover the truth of a hypothesis.

Transverse and Longitudinal Research

Transverse Research: Involves studying different variables at a specific point in time.

Longitudinal Research: Involves studying variables over an extended period.

Retrospective and Prospective Research

Retrospective Research: Observation units are classified based on the presence or absence of an effect, and the frequency of causal factors is recorded.

Prospective Research: Individuals are selected based on the presence or absence of exposures (inputs), and the frequency of the effect is recorded.

Case-Control Studies

• Combines advantages of retrospective and prospective designs.
• Observation units are chosen based on the effect (outcome).
• Causal factors are often observed in both cases and controls.
• Estimates the relative risk of contracting a disease concerning the presence of causal factors.

Experimental and Non-Experimental Research

Experimental Research: Experimental units are randomly allocated to different categories of causal factors, studying the effects that occur in each category.

Non-Experimental Research: Study units are classified into different categories of causal factors or effects, and the relationship between the two is studied.

Types of Statistics

Descriptive Statistics

Describes, analyzes, and represents a group of data using numerical and graphical methods to summarize and present the information contained within them.

Inferential Statistics

Relies on the estimation of probabilities and, from sample data, makes estimates, decisions, predictions, or other generalizations about a larger set of data.

Key Definitions in Research and Statistics

Individual:

A person or object that contains specific information to be studied.

Population:

A set of individuals or items that share certain common properties.

Population Size:

The total number of individuals composing a population.

Census:

The observation of all individuals within a population.

Sample:

A representative subset of a population.

Sample Size:

The number of individuals composing the sample.

Sampling:

Any process involved in obtaining samples.

Experiment:

Any process where each individual or element can be associated with a specific outcome or value, numerical or otherwise, from a predefined set of possible outcomes.

Random Experiment:

An experiment in which successive realizations under the same conditions produce different results (e.g., rolling a die).

Deterministic Experiment:

An experiment where the results are completely determined when the conditions for achieving them are set (e.g., calculating the trajectory of space travel).

Trial:

The concrete realization or single instance of an experiment.

Result:

The specific outcome obtained from a trial.