• Information we gather with experiments and surveys

• Statistics is the art and science of:
  • Designing Studies
  • Analyzing resultant data
  • Translating data into knowledge and understanding

• Design
• Description
• Inference

Aspects of a study:

Design

• Planning how to obtain data
  • ex. how to conduct the experiment
  • ex. how to select people for survey to insure trustworthy results

ASpects of a Study:

Description

• Summarizing the data
  • Methods for summarizing raw data
    • graphs or charts
    • numerical summaries (means, medians etc.)

Aspects of a Study:

Inference

• Making decisions and predictions
  • Methods of making decisions or predictions about a population based on data obtained rom a sample

• Entities that we measure in a study
  • Can be individuals, schools, etc.

• Population = all subjects of interest
• Sample = Subset of population for whom we have data
  • Statistical techniques used to make conclusions about population based on sample

• Methods for summarizing data summaries
  • ex. graphs, averages, percentages etc.

• Methods of making decision / predictions about population based on data from smaple of that population

• numerical summary of the population
  • Mean (μ mu)
  • Proportion (Ρ rho)

• Numerical summary of sample taken from population
  • Mean ([image] X-bar)
  • Proportion (^P imagine the ^ is sitting on top of P :P )

• Each subject in population has same chance of being included in sample
• Randomness crucial to insuring sample is representative of population
  • Only then could infrences can be made
• Predictions more accurate for larger samples

• Large sets of data usually organized in spreadsheet format
• Row contains measurements for particular subject
• Column contain measurements for particular characteristic.

• Existing archive - collection of data files
• check sources for reliability

• Short application program for performing specific task