Chap 3: Variables & Measurements

Question 1

What is a variable?

Answer 1

An aspect of a testing condition that can change or take different characteristics depending on different conditions.

Question 2

What is a dependent variable?

Answer 2

A measure of how much the subject’s behaviour changed based on the independent variable’s effects. Usually the variable that is being measured during an experiment.

Question 3

What is an independent variable?

Answer 3

The condition that is being manipulated or selected by the researcher to determine its effect on behaviour, or on the dependent variable.

Question 4

What are confounded variables?

Answer 4

Variables that cannot be separated from the independent variable, for example age or gender.

Question 5

What are quantitative variables?

Answer 5

Variables that vary in amount.

Question 6

What are categorical variables?

Answer 6

Variables that vary in kind.

Question 7

What are the 2 further categories of quantitative variables?

Answer 7

Discrete variables & continuous variables

Question 8

What are discrete variables?

Answer 8

Can only take certain individual values. For example, the number of pages in a book. (there are no X.5 pages)

Question 9

What are continuous variables?

Answer 9

Can take on any value in a certain range. For example, the temperature or the height of a person.

Question 10

What is the definition of measurement?

Answer 10

The process of assigning a number or a value to events or objects according to the rules.

Question 11

What are the 4 types of measurement scales?

Answer 11

Nominal

Ordinal

Interval

Ratio

Question 12

What is a nominal scale?

Answer 12

A measure that divides objects or events into categories according to their characteristics (similarities & differences). Gender and race are examples.

Question 13

What is an ordinal scale?

Answer 13

A measure that assigns objects or events a name and is arranged in order of their magnitude. For example, ranking someone’s preference of fruits.

Question 14

What is an interval scale?

Answer 14

Includes nominal and ordinal information, however, there are meaningful differences between each choice. The intervals between each choice are equal.

For example, a temperature scale, the difference between 10 and 20 degrees is the same as 20 and 30 degrees.

Question 15

What is a ratio scale?

Answer 15

Includes nominal, ordinal and interval information, however, there is a meaningful zero (starting) point.

For example, the speed of an object, there is a meaningful zero point, and 10 km/h is twice as fast as 5 km/h.

Question 16

What is reliability in terms of measurements?

Answer 16

The property of consistency of a measurement, meaning how often it gives the same result on different occasions.

Question 17

What is validity in terms of measurement?

Answer 17

Property which determines how accurately the test actually measures a particular measurement.

Question 18

What are some reliability measures for measurements?

Answer 18

Test-retest reliability

Internal consistency

Split-half reliability

Question 19

What is test-retest reliability?

Answer 19

Essentially testing the measure multiple times to determine whether it would yield the same results on every occasion.

High reliability measures would yield the same results whereas low reliability measures would yield different results.

Question 20

What is internal consistency?

Answer 20

Concerns whether the items on a test are measures of the same thing.

High reliability is when all items measure the same thing, whereas low reliability is when some items do not measure the same thing.

Question 21

What is split-half reliability?

Answer 21

When items on a test are divided into 2 different sets, as if they are 2 different tests.

A high reliability test would have a high split-half correlation.

Question 22

What are the 4 defined types of validity in terms of measurement?

Answer 22

Content validity

Construct validity

Criterion validity

Face validity

Question 23

What is content validity in terms of validity measures in measurements?

Answer 23

The test should sample a range of behaviour represented by the theoretical concept being tested.

“Does your test comprehensively assess all aspects represented by the theoretical concept?”

Question 24

What is criterion validity in terms of validity measures in measurements?

Answer 24

The test should correlate with other measures of the same theoretical concept.

For example, if the criterion of an intelligence test is whether it correlates with how well a child is doing in school at the time the test is given, it is called concurrent validity.

If the criterion of an intelligence test is how well the test can predict future performance of the child, such as graduation from university, it is called predictive validity.

Question 25

What is face validity in terms of validity measures in measurements?

Answer 25

A test should superficially test what it is supposed to test.

For example, a Rorschach inkblot test for personality has low face validity.

“Does the test appear to measure what you are trying to test on the surface?”

Question 26

What is construct validity in terms of validity measures in measurements?

Answer 26

A test that the measurements actually measure the constructs they are designed to measure and not anything else.

For example, a test for leadership ability should not test extraversion.

“Are you actually measuring what you are trying to measure?”

Question 27

What is a subject variable?

Answer 27

Variables that vary across participants and cannot be manipulated by the researcher. Age and race are examples of subject variables.