Biostatistics Notes

Introduction to Biostatistics

• Course Title: Biostatistics - An Introduction
• Department: Preventive Dentistry, Community Dentistry Division
• Institution: College of Dentistry, Jouf University

Uses of Biostatistics

• Data collection
• Data presentation (condensation)
• Data analysis
• Data interpretation
• Drawing conclusions

Types of Variables & Data

Quantitative Variables

• Measurable numerically
• Types:
  • Discrete
  • Continuous
  • Ratio
  • Interval
• Examples: Number of teeth, depth of gingival sulcus

Qualitative Variables

• Cannot assume numerical value
• Classified into categories
• Examples: Skin color, religion

Levels of Measurement

Interval vs. Ratio

• Both rank data and precise differences exist.
• Interval: No meaningful zero (e.g., IQ)
• Ratio: True zero present (e.g., test marks, time, speed)

Key Terminologies

• Incidence: Number of new cases.
• Prevalence: Total number of cases (old + new).
• Mean: Average value.
• Median: Middle value.
• Mode: Most frequently occurring value.