Anecdotal Evidence: Substantiating a claim with potentially biased stories, memories, etc., instead of scientific and statistically rigorous examination.

Selection bias: Inaccuracy from only studying a specific subpopulation that is different than the whole.

Confirmation bias: Inaccuracy from focusing on proving something you already believe.

Estimation: Using sample characters to generalize about the overall population.

Hypothesis testing: A scientific examination of whether an effect is likely by random chance or not.

Cross-sectional study: Snapshot of a group at a point in time.

Longitudinal study: Observes the same group repeatedly over time.

Cycle: One of the points in time a group was observed during a longitudinal study.

Respondents: Participant in a study.

Representative: Sample roughly estimates population.

Oversample: Sample has a higher percentage of a factor than would be found in the total population.

Codebook: Documents design of study.

Data cleaning: Filling in missing parts of the total data in an unbiased way reflective to the total population.

Chapter 3

Probability mass function: Maps each value to it's chance of occurring.

Normalization: Dividing a wide range of values by a common value (usually n or n/2) to get a smaller range of values for algorithmic efficiency.