0 Statistics 0

0 Statistics 0

1. Data sets

   • Population
     • Parameter: numerical description
   • Sample
     • Statistics: numerical description
     • Sample Techniques
       • Stratified Sample
         • Members or the population are divided into two or more subsets, then a sample is randomly selected from each subset.
       • Cluster sample
         • When the population naturally falls into subgroups, then divide into clusters.
       • Systematic Sample
         • Each member of the population is assigned a number, then they are ordered in some way and a random number is selected, then members are selected through regular intervals.
   • Types of Data
     • Qualitative data
       • Attributes, labels, or nonnumerical entries.
     • Quantitative data
       • Numerical measurements or counts
   • Levels of Measurement
     • Nominal Level of Measurement
       • Qualitative only.
     • Ordinal level of measurement
       • Qualitative or Quantitative
     • Interval level of Measurment
       • can be ordered, meaningful differences between data entries can be calculated.
     • Ration level of Measurement
       • zero entry is an inherent zero
   • Data Collection
     • Observational study
       • Researcher observes but does not change the existing conditions.
     • Experiment
       • A Treatment is applied to a part of the population and responses are observed.
       • Confounding variable
         • Occurs when an experimenter cannot tell the difference between the effects of different factors on a variable.
       • Blinding
         • The subjects do not know whether they are receiving a treatment or a placebo.
       • Randomization
         • Is a process of randomly assigning subjects to different treatment groups.
       • Replication
         • Repetition of experiment.
     • Simulation
       • Mathematical or Physical model to reproduce the conditions of a situation or process.
     • Survey
       • Investigation of one or more characteristics of a population.
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2. Branches of Statistics

   • Descriptive statistics
     •  organization, summarization, and display of data
   • Inferential Statistics
     • involves using a sample to draw conclusions about a population.