Statistics for CSAI 2

by Albert Major

POPULATIONS, SAMPLES, SAMPLING, THE MEAN, SAMPLING DISTRIBUTIONS, AND CONFIDENCE INTERVALS

Populations and Samples

Population

• A population is the full group you want to make a claim about.
• Examples:
  • All CSAI students.
  • All Dutch citizens.
  • All people who play an instrument.
  • All VR gamers aged 12 to 18.
  • All instances of a linguistic pattern in a text corpus.

Sample

• A smaller subset you collect data from.
• You use the sample because observing the full population is usually impossible.
• You hope the sample is representative enough to estimate the population well.

Goal of statistical inference

• Use the sample to estimate population parameters.
• Not to prove anything.
• You report evidence with uncertainty, not certainty

Types of Sampling

The lecture covers the types that matter for research design and for correctly interpreting scientific studies.

Simple Random Sampling

• Every member has equal chance of being selected.