MATH 125 - Chapter 1.1 Introduction to Statistics

Vocabulary flashcards covering fundamental statistical concepts, sampling methods, types of bias, experimental design terms, and key estimation formulas from MATH 125 Chapter 1.1.

Statistics

Using data to describe patterns, evaluate claims, and make decisions.

Population

The entire group the study aims to describe.

Target population

The intended group to describe; the people actually reached may differ.

Sample

The subset of the population observed or surveyed.

Parameter

A number describing a whole population.

Statistic

A number describing a sample.

Census

Collecting data from every member of the population.

Categorical / qualitative data

Labels or categories where arithmetic is not meaningful.

Quantitative data

Numerical counts or measurements where arithmetic is meaningful.

Sampling variability

Natural differences among random samples.

Sampling bias

A sampling method systematically underrepresents or overrepresents groups, causing the sample to fail to represent the population.

Simple random sampling

Randomly selecting individuals so every possible group of the chosen size has an equal chance of being selected.

Stratified sampling

Splitting the population into categories, then randomly selecting individuals from EACH category.

Quota sampling

Filling predetermined numbers from categories; not necessarily random within each category.

Cluster sampling

Randomly selecting SOME whole groups and surveying all of their members.

Systematic sampling

Choosing every $n^{\text{th}}$ individual, ideally after a random start.

Convenience sampling

Selecting people who are easiest to reach.

Voluntary response sampling

A sampling method where people opt in to participate.

Voluntary response bias

A bias that occurs when people who opt in have unusually strong opinions.

Self-interest study

A study where the sponsor or researcher benefits from a particular outcome.

Response bias

A bias where respondents give inaccurate answers, including from memory errors.

Perceived lack of anonymity

A concern where respondents fear the consequences of giving honest answers.

Loaded question

Question wording that pushes people toward an answer.

Non-response bias

A bias occurring when people who decline or drop out differ from those who respond.

Observational study

A study that measures or observes subjects without assigning a treatment.

Experiment

A study where researchers assign a treatment and measure its effect.

Explanatory / independent variable

The factor being changed or compared in a study.

Response / dependent variable

The outcome measured in a study.

Treatment

A condition applied to an experimental unit (a person or object studied).

Control group

A comparison group that does not receive the new treatment; it may receive a placebo or standard treatment.

Random assignment

Randomly placing participants in treatment groups to help balance other factors.

Confounding

A situation where multiple factors change simultaneously, making the cause of an effect unclear.

Placebo

An inactive imitation treatment.

Placebo effect

Changes in subjects associated with expectations about a treatment.

Blind study

A study in which participants do not know their treatment assignment.

Double-blind study

A study in which participants and those interacting with/evaluating them do not know treatment assignments.

Sample proportion

The ratio calculated as $\frac{\text{Number with characteristic}}{\text{Number sampled}}$.

Estimate a population count

A calculation determined by $\text{Sample proportion} \times \text{Population size}$.