Statistical Concepts

Statistics

The field of study and a set of methods used for collecting, organizing, analyzing, interpreting, and presenting data.

Variable

Any characteristic, number, or quantity that can be counted or measured.

Qualitative Variables (Categorical Variables)

Variables that represent categories, groups, or labels without numerical value.

Nominal Variables

Categories with no inherent order or ranking (e.g., gender, types of fruits).

Ordinal Variables

Categories with a specific order but unequal intervals between them (e.g., education level, customer satisfaction ratings).

Quantitative Variables (Numerical Variables)

Variables representing measurable quantities expressed as numbers.

Continuous Variables

Variables that can take an infinite number of values within a given range (e.g., height, temperature).

Discrete Variables

Variables that take specific, distinct values, often whole numbers (e.g., number of children in a family, number of cars in a parking lot).

Population

The entire group or set of individuals, objects, or data points of interest in a study.

Parameter

A numerical value that summarizes a specific characteristic of a population.

Sample

A subset of the population selected for analysis.

Descriptive Statistics

Statistics that summarize a dataset using measures such as mean, median, mode, range, variance, and standard deviation.

Inferential Statistics

Techniques used to draw conclusions or make predictions about a population based on a sample.

Univariate Analysis

Analysis focused on a single variable, examining distribution, central tendency, and spread.

Bivariate Analysis

Analysis examining relationships between two variables (e.g., correlation between education level and income).

Multivariate Analysis

Analysis dealing with three or more variables to explore complex relationships.

Slovin’s Formula

where:

• n = sample size

• N = total population

• e = margin of error

This is used to determine sample size.