Stats Unit 1

Statistics

The science of collecting, organizing, analyzing, and interpreting data to make decisions.

A Statistic

A numerical description that summarizes a sample characteristic.

Datum

A single data value (singular of data).

Data

The collection of facts, measurements, or observations (plural of datum).

Population

The complete set of individuals or items being studied.

Sample

A subset of the population used to represent the whole.

Parameter

A numerical description that summarizes a population characteristic.

Descriptive Statistics

Methods for organizing, displaying, and describing data (e.g., graphs, averages).

Inferential Statistics

Methods for drawing conclusions or making predictions about a population based on a sample.

Qualitative Data

Non-numerical data that describes qualities or categories.

Quantitative Data

Numerical data that represents counts or measurements.

Nominal

Data categorized only by names or labels, with no meaningful order (e.g., eye color).

Ordinal

Data that can be ranked, but differences between values are not meaningful (e.g., class rank).

Interval

Ordered, measurable data where differences are meaningful, but no true zero exists (e.g., temperature in °C).

Ratio

Data with a meaningful order, meaningful differences, and a true zero (e.g., weight, height).

Experiment

A study in which researchers apply a treatment to measure its effect.

Simulation

A model used to imitate real-world situations or processes to collect data.

Census

A count or survey of an entire population.

Sampling

Collecting data from a part of the population to make inferences.

Observational Study

A study where data are observed and recorded without influencing the subjects.

Simple Random Sample

Every individual and every possible group has an equal chance of being selected.

Cluster Sampling

The population is divided into groups (clusters); entire clusters are randomly chosen.

Stratified Sampling

The population is divided into subgroups (strata) by shared characteristics, and samples are taken from each.

Systematic Sampling

Every kth member of the population is chosen.

Convenience Sampling

Samples are taken from those easiest to access (not very reliable).

Randomization

Using chance to assign subjects to treatments to reduce bias.

Treatment

The condition applied to experimental units.

Control Group

Group not given the treatment, used for comparison.

Experimental Group

Group that receives the treatment.

Placebo

A fake treatment used to test if results are due to the treatment itself or expectations.

Explanatory Variable

The variable that is manipulated (independent variable).

Response Variable

The outcome that is measured (dependent variable).

Retrospective Study

A study that looks back at data from the past.

Prospective Study

A study that follows subjects forward in time to collect data.

Replication

Repeating an experiment or having a large enough sample size to ensure results are reliable.

Inherent Zero

A zero that implies 'none' or complete absence (e.g., zero dollars means no money).

Running

Processing data continuously as new data come in (like a 'running total').

Chunking

Breaking data or tasks into smaller, manageable groups for analysis or memory purposes.