Chapter 1 - Quantitative Methods in Psych

Statistics (1)

Numbers that summarize whole sets of data

Statistics (2)

The science of collecting and analyzing numerical data in large quantities, usually with the help of software programs.

Statistical Literacy

The ability to understand, evaluate, and use data and statistics.

Stacking the Deck

A questionable statistical practice that involves using only data that confirm a particular position while ignoring contradictory evidence. Also called cherry-picking.

Conflict of Interest

Occurs when a researcher feels compelled to produce the results that the client wants.

Outcome Data

Data used to measure the effectiveness of experimental manipulation.

Hypothesis

A proposed explanation made on the basis of limited evidence that serves as a starting point for further research or study.

HARKing

Hypothesizing after results are known, or revising a hypothesis after the results of a study are known.

Data

Observations or measurements.

Dataset

A collection of data (observations or measurements).

Scientific Method

A systematic procedure for observing and measuring phenomena (observable things) to answer questions about what happens, when it happens, what causes it, and why.

Theory

A set of interconnected ideas that attempts to explain what is observed and makes predictions of future events.

Treatment Group

The group in an experiment that is exposed to the scientific manipulation.

Control Group

In a research experiment, the group that represents the baseline or the population without any experimental manipulation.

Placebo Group

In research, a group that receives an inert treatment.

Survey or Poll

In research, a questionnaire used for collecting people's opinions.

Population

The larger group that a researcher is interested in studying and from which the researcher needs to collect data.

Sample

In statistics, a smaller set selected from a population, generally intended to represent the population as a whole.

Representative

Demographically similar to the population of interest.

Variable

A condition or a characteristic that can have different values.

Independent Variable (IV)

The variable that is manipulated by a researcher.

Dependent Variable (DV)

The outcome variable that is measured in an experiment.

Random Assignment

An experimental technique in which researchers randomly assign participants to a condition of the independent variable.

Quasi-experimental method

A research design that does not randomly assign participants to conditions.

Score (or Response)

A person's response on a scale; used to measure a variable.

Anchors

A visual or verbal description of each possible response on a scale.

Quantitative data

Numeric data that are used to measure, categorize, or order some aspect of a variable.

Qualitative data

Nonnumeric data that can be collected in a research study.

Continuous Data

The numbers used to measure a quantity. An infinite number of possible values fall between two specific values.

Categorical data

Data in which numbers are substitutes for categories.

Scale of Measurement

The categories used to measure a variable: nominal, ordinal, interval, and ratio.

Nominal data

Data that use numbers as placeholders for categories.

Ordinal data

Data that are in a meaningful order but lack a true zero or equal distance between variables.

Interval data

Data with an equal distance between numbers. Order matters, but zero does not indicate the absence of the variable.

Ratio data

Data with even space between scores, ordered from smallest to largest. A score of zero indicates the absence of the thing being measured.