intro

• Random Sampling


  Selected by using chance methods or random numbers
• Systematic Sampling


  Numbering each subject of the population then selecting every kth subject
• Variable


  A characteristic or attribute that assumes different values
• Experimental study groups

  • Treatment group
  • Control group
• Population


  Consists of all subjects (human, animals, machines, places) being studied for which we have an interest at a particular time
• Subgroups of quantitative variables

  • Discrete variables (finite)
  • Continuous variables (infinite)
• Sample

  Group of subjects or entities selected from a population
• Main branches of statistics

  • Descriptive Statistics
  • Inferential Statistics
• Other sampling methods

  • Convenience sampling
  • Sequential sampling
  • Double sampling
  • Multi-stage sampling
• Advantages and disadvantages of observational studies

  • Advantages: Usually occurs in a natural setting, Can be done using variables that cannot be manipulated by the researcher
  • Disadvantages: No definite cause-and-effect, Results subject to inaccuracies of those who collect the data
• Measurement scales

  • Nominal Level of Measurement
  • Ordinal Level of Measurement
  • Interval Level of Measurement
  • Ratio Level of Measurement
• Types of statistical studies

  • Observational studies
  • Experimental studies
• Cluster Sampling


  Population is divided into groups called clusters by some means, researcher randomly selects some of these clusters and uses all members of the selected clusters as subjects
• Types of research variables

  • Independent variables (IV)
  • Dependent variables (DV)
• Advantages and disadvantages of experimental studies

  • Advantages: Precise dosage of medicines, accurate test measurements
  • Disadvantages: Unnatural settings, Hawthorne effect, Confounding variable
• Stratified Sampling

  Obtained by dividing the population into groups (strata) according to some characteristic, then sampling from each group randomly
• Statistics

  • Science of conducting studies to collect, organize, summarize, analyze, and draw conclusions from data (drawing inferences from a sample of population)
  • Biostatistics: When data analyzed are derived from the biological sciences, medicine, and public health