Stats - Concepts or sampling - 1

the two types of variables

Categorical variables and quantitative variables.

categorical variable

divides data into groups like color

quantitative variable

measures numerical quantities

Population

all individuals of interest

Sample

subset used to infer about the population

notation for population

N (capital N)

sample size

n

census

A survey of the entire population.

simple random sample

when everyone has an equal chance of being selected

What are other sampling methods?

Stratified random sampling, cluster sampling, and convenience sampling.

sampling bias

when the sample does not match population proportions

What is measurement bias?

when the questions are poorly worded or confusing to understand

What is volunteer bias?

When only people with strong opinions respond (e.g., course evaluations).

response bias

Inaccurate self-reporting due to wording or sensitivity of questions.