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.

Singing vs. Storytelling

Biostatistics

생물은 OOOOO. 통계는 OOOOO. 생물통계는 OOOOO.

Biostatistics

나는 너보다 키가 크다. 우리는 너희보다 키가 크다.

Biostatistics

가천인은 하버드인보다 키가 크다.

Lecture 2

http://en.wikipedia.org/wiki/File:Earth_Eastern_Hemisphere.jpg

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