CHap 3: Variables

Question 1

What are the limitations of operational definition?

Answer 1

• not a one-on-one relationships between variables and measurements
• operational definitions might leave out important components of construct
• sometimes include components that are not part of construct

Question 2

What is the difference between confounding and extraneous variables?

Answer 2

Confounding-> uncontrolled variable that is allowed to vary systematically with the IV and has the potential to influence the DV
Extraneous-> uncontrolled variable that can influence the DV OR could influence the IV BUT not both

Question 3

Explain the four types of scales of measurement

Answer 3

Nominal->qualitative
Ordinal-> ordered
Interval and Ratio-> equal intervals
(interval= arbitrary zero)

Question 4

What is a construct?

Answer 4

Unobservable internal mechanism that accounts for externally observed behaviour

Question 5

What is an operational definition?

Answer 5

procedure for indirectly measuring and defining a variable that cannot be observed or measured directly

Question 6

What does a positive relationship between two variables means?

Answer 6

It means that the two variables change in same direction (correlation near +1.00)

Question 7

What is the validity of an experiment?

Answer 7

measurement procedure is actually measuring what it claims to be measuring

Question 8

What is a face validity?

Answer 8

unscientific form of validity demonstrated when a measurement procedure superficially appears to measure what it claims to measure

Question 9

What is a concurrent validity?

Answer 9

scores obtained from a new measure directly related to scores from an established measure of the same variable

Question 10

What is a predictive validity?

Answer 10

scores obtained from a measure accurately predict behavior according to a theory

Question 11

What is a construct validity?

Answer 11

scores obtained from a measurement procedure behave exactly the same as the variable itself

Question 12

What is a convergent validity?

Answer 12

strong relationship between the scores obtained from two different methods of measuring the same construct

Question 13

What is a divergent validity?

Answer 13

little or no relationship between the measurements of two different constructs

Question 14

What is the reliability of an experiment?

Answer 14

produces identical results when it is used repeatedly to measure the same individual under the same conditions

Question 15

What are the three types of reliability?

Answer 15

Test-retest reliability→ Successive measurements
- if different tests are used for test and retest→ parallel-forms reliability
Inter-rater reliability→ measurements by two observers
Split-half reliability→ Internal consistency

Question 16

What are the common source of error coming from the participant?

Answer 16

Reactivity-> modify natural behaviour because are being measured
Response set->a readiness to answer in particular way

Question 17

What are the common source of error coming from the equipment?

Answer 17

• sensitivity of equipment
• clarity of instructions, appropriateness
• ceiling effect→ measurement not sensitive enough to detect difference at high end of the scale
• floor effect→ measurement not sensitive enough at low end

Question 18

What are the common source of error coming from the environment?

Answer 18

• comfort, presence of others, distractions
• Social facilitation

Question 19

What are the common source of error coming from the experimenter?

Answer 19

Expectancy (ex: experiment with “bright rat” and “dull rat” influenced by students)

Question 20

What are the ways a participant might act when being measured?

Answer 20

• good participant role→ want to follow the hypothesis
• negativistic participant role→ answers contrary to hypothesis
• apprehensive→ believe that they’re gonna be judged
• faithful→ answers truthfully

Question 21

What are the ways to reduce measurement error?

Answer 21

Standardization of participants, test protocol, environment, scoring (pilot testing)