Introduction to Statistics

Introduction to Statistics

• Definition: Statistics is the study of numerical data and methodologies for data collection, presentation, analysis, and application.

Levels of Measurement

• Nominal Data: Categories without order (e.g., medical diagnosis: yes/no).

• Ordinal Data: Categories with rank order but unknown differences between ranks.

• Interval Data: Equal intervals without absolute zero (e.g., temperature).

• Ratio Data: Equal intervals with absolute zero, indicating complete absence of measurement (e.g., weight).

Importance of Statistics in Nursing

• Enhances patient care and outcomes.

• Supports evidence-based practice for better decision-making.

• Applicable in various areas: medication administration, public health, research, resource management.

Basic Terms

• Population: Entire group of observations.

• Sample: Subset of the population for analysis.

• Variable: Characteristic that can vary.

• Data: Collected information for statistical analysis.

• Time Series Data: Collected over time.

• Cross-Sectional Data: Collected at a single point in time.

• Experimental Studies: Control and randomization methods.

• Nonexperimental Studies: Observational approaches.

Descriptive Statistics vs Statistical Inference

• Descriptive Statistics: Collection and description of data without inferences.

• Statistical Inference: Drawing conclusions about a population from sample data.

Types of Statistical Analyses

• Non-Parametric Statistics: Used for nominal and ordinal data; not reliant on normal distribution.

  • Central tendency: Mode for nominal; Median for ordinal.

  • Range for dispersion in ordinal data.

• Parametric Statistics: Used for interval and ratio data; assumes normal distribution.

  • Conditions: Sample must be normally distributed, continuous data, random sampling, and independent observations.

References

• Grove, S. K., & Cipher, D. J. (2025). Statistics for nursing research: A workbook for evidence-based practice. Elsevier Health Sciences.