P3

• Statistics


  A collection of methods for planning experiments, obtaining data, and then analyzing, interpreting and drawing conclusions based on the data
• Data


  The values that the variables can assume
• Variable


  A characteristic that is observable or measurable in every unit of universe
• Population


  The set of all possible values of a variable
• Sample


  A subgroup of a population
• Parameter


  The measures of the population
• Statistics


  The measures of the sample
• Classification of Variables


  • Qualitative
  • Quantitative
• Qualitative Variables


  Words or codes that represent a class or category, express a categorical attribute
• Quantitative Variables


  Numbers that represent an amount or a count, numerical data with sizes that are meaningful
• Quantitative Variables


  • Discrete
  • Continuous
• Discrete Variables


  Data that can be counted
• Continuous Variables


  Data that can assume all values between any two specific values
• Types of Statistical Data

  • Numerical
  • Categorical
• Numerical Data


  Data that have a meaning as a measurement
• Categorical Data


  Data that represent characteristics, can take on numerical values
• Levels of Measurement


  • Nominal
  • Ordinal
  • Interval
  • Ratio
• Nominal Level


  Data that consists of names, labels, or categories only

  
• Ordinal Level


  Data that is arranged in some order, but differences between data are not known
• Interval Level


  Data that is the same as ordinal level, with the additional property that meaningful amounts of differences between the data can be determined
• Ratio Level


  An interval level modified to include the inherent zero starting point, possesses a meaningful absolute, fixed zero point and allows all arithmetic operations
• Four Basic Methods of Sampling

  • Simple Random Sampling
  • Systematic Sampling
  • Stratified Sampling
  • Cluster Sampling
• Simple Random Sampling 


  this is done by using chance or random numbers.
• Systemic Sampling

  this is done by numbering each subject of the population and then selecting nth number
• Stratified Sampling

  If a population has a distinct groups. It is possible to divide the population into this groups and to draw SRS’s from each of the groups.
• Cluster Sampling


  If a population has a distinct groups. It is possible to divide the population into this groups and to draw SRS’s from each of the groups.