Lecture Notes on Biostatistics

Introduction to Biostatistics

• Definition: The application of statistics to the analysis of biological data.
• Philosophy: Considered as a search for truth.
• Branches:
  • Statistical genetics
  • Clinical trials
  • Exposure methods
• Limitations: Cannot prove hypotheses, only provides weight of evidence.

Importance of Biostatistics

• Responsibility: Scientists must accurately explain scientific findings to the public.
• Public Understanding: Most of the public does not understand statistics but wants clear answers.
• Application: Interpreting data, explaining study results, and evaluating evidence.
• Misinformation: Addressing poor use of statistics and poor study designs.
• Career Relevance: Essential for public health policy and interpreting scientific studies.

Role in Scientific Research

• Inference: Making inferences about populations based on samples.
• Study Comparison: Comparing results across multiple studies to form conclusions.
• Sample Size: Estimating sufficient sample size for studies, including power calculations.

Example: Gallup Poll

• Context: Gallup poll on congressional approval in 2013.
• Sample Size: 1,039 adults with a 95% confidence margin of ±4 percentage points.
• Population Size: Approximately 316 million U.S. adults.
• Sampling Validity: Discussed validity of the small sample size representing a large population.

Population vs. Sample

• Definitions:
  • Population: Totality of subjects under study.
  • Sample: Subset of the population used for measurements.
• Sampling Error: Differences in study methods can introduce biases or errors.

Statistical Descriptions

• Parameters: Describes populations, often using Greek symbols.
• Sample Statistics: Estimates population parameters, often using Roman letters.
• Sampling Impact: How sampling can affect research outcomes.

Sampling Types

• Random Sample: Eliminates bias, most reliable.
• Stratified Random Sample: Ensures balance across strata, such as gender.
• Sample of Convenience: Risk of bias, not representative of the population.

Homework and Discussion

• Assignments:
  • Watch John Oliver's episode "Science" and a Colbert Report episode on the 2012 election.
  • Familiarize with papers by Shikuma, Zhang, and Arshad for discussion.