Experimental Design, Sampling Methods: Research Methods

Question 1

Independent groups design

Answer 1

Ppts only take part in one condition

Question 2

Independent groups evaluation

Answer 2

+ less chance of demand characteristics, order effects eliminated
- ppt EV are threat to internal validity, more costly and time consuming as more participants needed

Question 3

Repeated measures design

Answer 3

When participants take part in both conditions

Question 4

Repeated measures evaluation

Answer 4

+ ppt Er reduced, less costly and need less ppt
- increased chance of demand characteristics, order effects are threat to internal validity

Question 5

Matched pairs design

Answer 5

Ppt only take part in one condition but they are matched on a new characteristic with another ppt and random allocation used to sign each ppt to each condition

Question 6

Matched pairs evaluation

Answer 6

+ ppt EV controlled for, less costly and time consuming, order effects eliminated, demand characteristics are reduced
- no EV ppt are fully accounted for, time consuming to match ppt

Question 7

Random sampling

Answer 7

Every member of target population have equal chance of being picked. 1. Need sampling frame which is complete list of all members of the population 2- all names assigned number 3. Sample is randomly selected for example by computer based randomiser

Question 8

Random sampling evaluation

Answer 8

+ No bias with method,
- takes more effort, doesn’t guarantee an unbiased sample

Question 9

Opportunity sampling

Answer 9

Involves recruiting anyone who happens to be available at time of study, go somewhere they’re likely find to target population and waste people to take part.

Question 10

Opportunity sampling evaluation

Answer 10

+ simple, quick, easy and cheap, useful for naturalistic experiments
- unrepresentative,

Question 11

Volunteer sampling

Answer 11

When people actively volunteer to be in a study by responding to advert.

Question 12

Advantages of volunteer sampling

Answer 12

Most convenient and economical way to gather wide group of people especially online

Question 13

Disadvantages of volunteer sampling

Answer 13

Sampling bias- more altruistic and people who have more time will volunteer, may end up with same type of people

Question 14

Systematic sampling

Answer 14

Involves selecting names from a sampling frame at regular intervals. Sampling frame put in alphabet order, sampling system nominated eg every 3rd person, works through whole sample list

Question 15

Advantages of systematic sampling

Answer 15

Simple to conduct, more evenly sampled using objective system

Question 16

Disadvanges of systematic sampling

Answer 16

Not truely unbiased as not all people have equal chance of being selected therefore representativeness is not guaranteed

Question 17

Stratified sampling

Answer 17

Ppts selected from different stratas (subgroups) in the target population in proportion to the subgroup’s frequency in the population. Chose strata, identify how many of the population is in the strata and work out the percentage then use the same percentage for the sample.

Question 18

Advantages of stratified sampling

Answer 18

Most representative sampling method as there is equal representation of all subgroups making generalisations more possible

Question 19

Disadvantages of stratified sampling

Answer 19

Knowledge of population characteristics required which may not be available, time consuming dividing population into stratum’s and then randomly selecting