Introduction to Biostatistics

Statistics: Science of collection, organization, presentation, analysis, and interpretation of numerical data.
BIOSTATISTICS: Term used when tools of statistics are applied to data that is derived from biological sciences such as medicine.
Common Terms:
- Population
- Sample
- Parameter
- statistic

Qualitative Data:
- No notion of the magnitude or size of the characteristics or attribute; cannot be measured.
- Classified by counting individuals having the same characteristics or attribute.
- Examples: attacked, escaped, died, cured, vaccinated, males.
- Expressed as a ratio, proportion, percentage, or a rate.
- Categorized into Nominal and Ordinal.
Quantitative Data:
- Any character, characteristic, or quality that varies is a variable.
- Characteristics and frequency both vary from person to person as well as from group to group.
- Examples: blood pressure, height, weight.
- Categorized into Discrete and Continuous.
Level of Measurement (N-O-I-R):
- Nominal
- Ordinal
- Interval
- Ratio

Primary sources: First hand information where data is obtained by the investigator himself.
Secondary sources: Utilization of already recorded data to serve the objective of the study (e.g., records of OPD of Govt. clinics).
Main sources for collection of medical statistics:
- Survey
- Questionnaire
- Observation
- Interview
- Observation