Lesson 8- Reliability, Validity & Control of Extraneous Variables

Question 1

Define reliability

Answer 1

Reliability- consistency of study- study repeated again & same results gained

Question 2

What are the 2 general types of reliability?

Answer 2

1) Internal reliability

2) External reliability

Question 3

What is internal reliability?

Answer 3

Internal Reliability- test & results gained consistent within itself- split-half technique assesses internal reliability of questionnaires e.g. questionnaire split in ½ & if pps score similarly both halves of questionnaire then questions measuring same factors & … internal reliability

Question 4

What is external reliability?

Answer 4

External Reliability- test & results gained consistent over ⏰- test-retest method assesses external validity- e.g. study conducted once & again in future- if results similar then reliable

Question 5

Define validity

Answer 5

Validity- study measuring what it intends to measure (fulfils aim of study)

Question 6

What are the 4 types of validity?

Answer 6

1) External (ecological) Validity
2) Participant Validity
3) Temporal Validity
4) Internal Validity

Question 7

Define external validity

Answer 7

External Validity- findings of study generalised to other settings

Question 8

Define internal validity

Answer 8

Internal Validity- outcome of study direct result of manipulation of IV & ✖️ by EV- For study to have internal validity EV must be well controlled

Question 9

Define participant validity

Answer 9

Participant Validity- results from pps used in study generalised to target population

Question 10

Define temporal validity

Answer 10

Temporal Validity- results from study generalised to ppl in today’s modern society (over ⏰)

Question 11

What are the 3 types of extraneous variables?

Answer 11

1) Participant variables
2) Experimenter variables
3) Situational variables

Question 12

What are participant variables?

Answer 12

Participant Variables- characteristics of pps affect DV- appropriate experimental design helps to overcome this EV- e.g. Matched pairs & repeated measures design
- Repeated measures- same pps used-> order effects- resolve by counterbalancing (split pps)

Question 13

What are experimenter variables?

Answer 13

Experimenter Variables- experimenter can affect DV- e.g. personality, appearance, conduct- resolved by standardisation- experimenter acts in similar way with all pps & follows script- same manner & tone

Question 14

What are situational variables?

Answer 14

Situational Variables- factors in environment affect DV (e.g. time of day, noise etc.)- resolved by standardisation (all conditions, materials, instructions same for all pps)

Question 15

What are investigator effects?

Answer 15

Investigator Effects- investigators influence results of study

Question 16

What are the 2 ways in which investigator effects can occur?

Answer 16

1) Physical characteristics of investigator e.g. age etc- resolve using script- see ⬆️
2) If investigators know hypothesis -> bias in interpretation of results- overcome by double blind technique (neither pps nor investigator know aim of study-> ⬆️ valid data)

Question 17

What are demand characteristics?

Answer 17

Demand Characteristics- EV- pps guess aim of research

Question 18

What are the 4 ways in which pps show demand characteristics (what do pps do)?

Answer 18

1) Pps please experimenter by giving results they 🤔 experimenter wants
2) Pps annoy researcher by giving incorrect results (screw you effect)
3) Act unnaturally out of nervousness
4) Acting unnaturally out of social desirability

Question 19

How do you overcome demand characteristics?

Answer 19

Overcome by single blind technique- pps ✖️ know aim of study … ✖️ influence 🏃‍♂‍- ⬆️ difficult in repeated measures design (same pps used)