research planning and design lecture 2

Question 1

main goals and features of experiments

Answer 1

• establish a causual relationship between variables
• measure the effect of one variable on another via manipulation
• must involve the active intervention of the researcher
• controlled environment
• control of extraneous variables

Question 2

systematic manipulation

Answer 2

deliberate and controlled alteration of one or more variables in an experiment to observe its effect on other variables.
- changing the level/ condition of independent variable systematically.

Question 3

single factor two level design

Answer 3

= one independent variable, two levels

Question 4

single factor multi level design

Answer 4

= one independent variable, more than two levels

Question 5

within subject design/ repeated measures design

Answer 5

= all participants are exposed to all levels/ conditions of the IV at different times

Question 6

between subject design/ independent design

Answer 6

= different participants are exposed to different levels of the IV

Question 7

extraneous variables

Answer 7

= any other variable apart from the IV and DV that could affect your outcome
- if it is not controlled can become a confounding variable
- example, age, time of testing

Question 8

confounding variables

Answer 8

= a extraneous variable that varies systematically across levels of IV

Question 9

Random assignment + block randomisation

way to control for confounding variables

Answer 9

1.) each participant has the same chance of being assigned to each condition, assignment of each participant is independent of all the others.
2.all the conditions occur once in the sequence before any of them is repeated.

Question 10

benefits of within-subject design

Answer 10

• maximum control of extraneous variables
• more powerful
• smaller sample size needed

Question 11

disadvantages of within subject design

Answer 11

• not practical with all designs
• carryover effects (repeated practice, fatigue, order effects) -> solution to this is counterbalancing

Question 12

benefits and cost of between subject design

Answer 12

• no carryover effects
• independent scores
• less time per participant
• practical for designs where its not possible to have participants in more than one condition
• needs a larger sample size

Question 13

counterbalancing

Answer 13

complete counterbalancing = equal number of participants complete each possible order of conditions -> might not be possible with large number of conditions (lots of different orders)

random counterbalancing = randomly assorted, not paying attention to how many people in each group

latin square = each condition appears exactly once in each position, means that each condition has an equal chance of being experienced in every position -> allows for fewer participants

Question 14

randomised control trial

Answer 14

= experiments done in the field to investigate the effectiveness of a treatment/ intervention
- only difference we should be able to see is the outcome of the variable being studied

placebo effect solution > double/ single blind

Question 15

internal validity

Answer 15

• ## tests if we can we confidently infer a causal relationship between variables without the influence of other factors or variables.

Question 16

external validity

Answer 16

= the degree to which we can generalise the findings to other people, times or settings - real world environment

• mundane realism = when the participants and the situation studied are similar to those that the researcher wants to generalise to

-psychological realism = same mental processes used in lab and real world