Post on 16-Sep-2020
Biostatistics (생물통계학)
Lecture 2 Introduction to Data Analysis
Doo-Hyung Lee, Department of Life Sciences
General information
• 이두형: DL343@gachon.ac.kr; 진리관 403C; 031-750-5408
• Office hours: by appointment
• Textbook: Glover & Mitchell, An Introduction to Biostatistics, McGraw-Hill
I was in the subway yesterday.
Biostatistics
생물은 OOOOO. 통계는 OOOOO. 생물통계는 OOOOO.
Biostatistics
나는 너보다 키가 크다. 우리는 너희보다 키가 크다.
Biostatistics
가천인은 하버드인보다 키가 크다.
Lecture 2
Scientific method
1. Observation of a particular event
2. Statement of the problem
3. Formation of a hypothesis
4. Making a prediction
5. Design of the experiment
1. Observation of a particular event
• Quantitative observations:
• Qualitative observations:
2. Statement of the problem
• A series of observations often leads to the finding of a particular problem or unanswered question.
• This usually takes the form of a “why” question.
3. Formulation of a hypothesis
• A hypothesis is a “tentative” explanation for the observations made.
• A good hypothesis suggests a cause and effect relationship and is testable.
4. Making a prediction
• Predictions take the form of an “if-then”.
5. Design of the experiment
• One goal: to test the hypothesis.
5. Design of the experiment
• How would you design an experiment to test the diet hypothesis in the hypertensive population?
Bryan Butler said….
Setting up a controlled experiment
Setting up a controlled experiment
Control Treatment
Setting up a controlled experiment
Control Treatment
Control Treatment
Setting up a controlled experiment
• Groups must be constructed without bias.
• Groups must be large enough to give the researcher an acceptable level of confidence in the results
• How large a change is significant enough to support the hypothesis?
I wish I could….
I wish I could….
Populations vs. Samples
• Koreans are taller than Americans.
• Ladybeetles in Korea are larger than ones in the U.S.
Populations vs. Samples
• Koreans are taller than Americans.
• Ladybeetles in Korea are larger than ones in the U.S.
Population (parameter)
Sample (statistic)
OK, now I got some data, then so what?
vs.
OK, now I got some data, then so what?
vs.
vs.
Let’s summarize the data
• Measures of central tendency – Mean – Median – Mode
• Measures of dispersion and variability
– Range – Variance – Standard deviation
Lecture 2
• Scientific method
• Populations vs. samples
• Measures of central tendency
• Measures of dispersion and variability