Lecture 2

Goal of Statistical Study

• The goal of the statistical study is to find out the particular characteristics of the population
• Population is the complete set of people or things being studied
• Population parameters are specific characteristics of the population

Types of Statistical Study

• Experimental study 主动生产数据
  • The study that researchers apply some treatments and observe its effects on the subjects of the experiment
  • It is an active data production 主动生产数据
  • For example: medical study
  • Treatment group vs. Control group (实验组, 对照组)
    • 选组的要求: Randomization, sufficiently large number of subjects or participants
  • Placebo Effect 安慰剂效应
    • Blinding: Single Blind (单盲, 实验人员知道) vs. Double Blind (双盲, 没人知道)
• Observational study 观测数据
  • The study that researchers observe or measure characteristics of the subjects, but do not attempt to influence or modify these characteristics
  • It is a passive data collection
  • For example: opinion poll, survey