Section1.1

Statistics

The science of planning studies and experiments; obtaining data; and organizing, summarizing, presenting, analyzing, and interpreting those data.

Data

Collections of observations, such as measurements, genders, or survey responses.

Population

The complete collection of all measurements or data that are being considered.

Census

The collection of data from every member of a population.

Sample

A subcollection of members selected from a population.

Voluntary Response Sample

A sample where respondents decide themselves whether to be included; often leads to biased results.

Statistical Significance

Achieved if the likelihood of an event occurring by chance is 5% or less.

Practical Significance

Refers to whether a treatment or finding has practical implications, even if it is statistically significant.

Sampling Method

The technique used to select members from a population for a sample.

Outliers

Data points that are very far away from almost all of the other data.

Context

What the data represent and the goal of the study.

Loaded Questions

Survey questions that are worded in a way that leads to misleading results.

Nonresponse

Occurs when a selected respondent refuses to respond or is unavailable.

Low Response Rates

When a survey has a low number of responses, affecting the reliability of the results.

Misleading Conclusions

Conclusions based on statistical analysis that are unclear or misrepresented.

Bias

A systematic error in data collection that results in an inaccurate representation of the population.