Psych Stats

Module

Statistics

The science of collecting, organizing, analyzing, and interpreting data.

Variable

A characteristic of an item or individual.

Independent Variable

Study hours (the cause) in the investigation of how study hours affects exam scores.

Data Example

5 hours (the actual value recorded from the variable 'Hours spent playing video games').

Population

Every single individual in a specific group.

Sample

A portion of the population collected for data.

Parameter

A measure that describes a population, such as the population mean.

Statistic

The measurement calculated from a sample, such as the sample mean.

Sample Mean

True (It is an example of a Statistic).

Qualitative (Categorical) Data

Type of data that represents groupings or labels.

Quantitative (Numerical) Data

An example is the number of siblings a person has.

Nominal Scale

Used for data that has categories with no rankings.

Ordinal Scale

Scale used to rate satisfaction as 'Low,' 'Medium,' or 'High' which has ranking.

Interval Scale

Measurement scale that has no zero point and only allows for addition and subtraction.

Ratio Scale

Measurement scale that involves a true zero point.

Interval Scale Example

IQ Scores or Temperature in Celsius.

Ratio Scale Classification

Height, weight, and salary are classified under this scale.

Mathematical Operations with Ratio Data

Multiplied, divided, added, and subtracted.

Standardized Tests Scale

Usually categorized as an Interval Scale.

Nominal Scale for Gender

Because it involves categories with no inherent mathematical ranking.

Dependent Variable

Weight loss (the effect) in the study on how diet type affects weight loss.

Categorical (Qualitative) Data

An example is the brand name of a smartphone.

Letter Grades Scale

Ordinal measurement scale.

Ratio Measurement

Allows you to say one value is 'twice as much' as another.

Celsius Temperature Scale

Interval because 0°C does not mean 'no temperature'; it is just a point on the scale.

Game Time Example

Identifies the hours spent playing video games as the independent variable.

Sample Mean Description

A value that describes a specific sample.

Survey Result Example

A survey result of 'Blue, Red, Green' is Categorical/Nominal data.

Ordinal Scale Distance Comparison

True (it tells you the order, but not the exact distance between values).

Primary Difference between Interval and Ratio

Ratio has a true zero point; Interval does not.