Variables, etc
 Page ID
 13571
Variables


Defining, Measuring, & Manipulating

IVs

DVs

Levels?


Confounding variables


Reliability

Validity

Operational definition of a variable

A definition of a variable in terms of operations/activities that a research uses to measure/manipulate it

Gives a variable a concrete definition so you can actually use it in an experiment, this allows the researcher to maintain consistency.

All variables involved in a study should be operationalized

Dependent Variables (what is measured)

Independent Variables (what is manipulated)

Levels of Measurement

Identity

Measurement in which different objects receive different scores


Magnitude / ordinality

Measurement in which the ordering of numbers reflects the ordering of variables


Equal Unit Size

A difference of 1 is the same amount throughout the entire scale

EX “the height difference between two people who are 64 inches tall and 65 inches tall is the same difference between those who are 72 inches tall and 73 inches tall”



Absolute Zero

Assigning a score of zero indicates an absence of the variable being measured

Scales of Measurement

Nominal

Ordinal

Interval

Ratio
Discrete Variables
Continuous Variables
Types of Measures

Selfreport

Tests

Behavioral

Physical
Reliability

Types of Reliability

test/retest

Alternateforms

Splithalf

Interrater


How to Measure Reliability
Validity

Content

Criterion

Construct