Stats terms to know

Sampling bias:

When a group is underrepresented in a sample compared to the population.

Voluntary bias:

When volunteers differ from the overall population, making results unrepresentative.

Response bias:

When the answers on a survey don't reflect the true feelings of the respondent.

Nonresponse bias:

When individuals selected to be in the sample who don’t respond to the survey have different opinion from those who do.

Systematic sample:

The members of the population are listed in some order. Then every Kth member is selected for the sample until a sample size is reached.

Stratified sample:

The population is split into groups (strata), and a sample is randomly taken from each group.

Cluster sample:

Randomly select entire groups (clusters) from the population and use everyone in those groups.

Convenience sample

A sample chosen from people who are easiest to reach, not randomly selected.

Observational study

When researchers watch and collect data without changing anything.

Designed experiment

A study where researchers intentionally change variables to see their effect on outcomes.

What is the formula for range?

largest value - smallest value