2.2.5 Sampling

Question 1

Opportunity sampling

Answer 1

When ptps are recruited based on who is most convinient or most available

e.g people walking by you in the street
e.g students at your school

Question 2

Give 1 advantage of Opportunity sampling

Answer 2

• the easiest methods - you jsut use the first sutiable ptps you can find
  > less time consuming to locate sample

Question 3

Give 1 disadvantage of Opportunity sampling

Answer 3

• biased > sample is drawn from a small part of target population
  e.g selecting sample from people walking around town would likely exclude ptps such as profesionals at work or people in rural areas

Question 4

Random Sampling

Answer 4

each item in a target population has an equal chance of being selected
- methods can be used such as lottery method and random number generators

Question 5

what is the Lottery Method of Random sampling

Answer 5

An easy method of random sampling where:

• list of people in target population is obtained
• all the names are put into a hat or barrel
• you select the number of names required

if a researcher is using this method for random allocation of ptps to groups, they might put first 10 names drawn in group A and second 10 names in group B

Question 6

what is a random number generator and how does it work

Answer 6

a device such as a calcualtor that has the fucntion to gernerate a random number

• every member of the target population gets numbered
• using, for example, mciorsoft excel you can type in a code to get a random number between 1-100

e.g =RAND(100)

Question 7

give 1 advantage of random sampling

Answer 7

• unbiased (all ptps have equal cahnce of selection)

Question 8

give 1 disadvantage of random sampling

Answer 8

• time consuming
  > need to create list of ptps in target population and contact all

Question 9

Snowball Sampling

Answer 9

current ptps recruit further ptps from among people they know
> sample group appears to grow like a snowball

Question 10

give 1 advantage of snowball sampling

Answer 10

• enables a researcher to locate groups of people who are difficult to access

e.g drug addicts

Question 11

give 1 disadvantage of snowball sampling

Answer 11

• the sample is not likely to be a good cross-section from the population becuase it is friends and family

Question 12

Self-Selected Sampling

Answer 12

advertisement in a newspaper or on a noticeboard or on the internet

Question 13

give 1 advantage of self-selected sampling

Answer 13

• gives access to a variety of ptps (e.eg everyone that reads the newspaper)
  > may make the same more representative and less biased

Question 14

give 1 disadvantage of self-selected sampling

Answer 14

• the sample is biased in other ways because ptps are liekly to be more highly motivated to be helpful, and/or with extra time on their hands

> results in volunteer bias

Question 15

Stratified Sampling

Answer 15

subgroups (strata) within a target population are identified (e.g boys and girls, or age groups: 10-12 years, 13-15 years)

• ptps are obtained from each strata in proportion to their occurence in the target population

for stratified, selected from the strata is done using a random technique
for quote, selcetion is done using a non-random technique

Question 16

give 1 advantage of stratified/quota sampling

Answer 16

• likely to be more representative than other methods
  > there is a proportional representation of subgroups

Question 17

give 1 disadvantage of stratified/quota sampling

Answer 17

• very time consuming to identify subgroups and then select ptps and contact them

Question 18

Systematic Sampling

Answer 18

Using a predetermined system to select ptps such as selecting every 6th, 14th, 20th (or whatever?!) person from a phonebook

• the numerical interval is applied consistently

Question 19

give 1 advantage of systematic sampling

Answer 19

• unbiased as ptps are selected using an objective system

Question 20

give 1 disadvantage of systematic sampling

Answer 20

• not truly unbiased/random unless you select a number using a random method and start with this person, and then select every Nth person

Question 21

Sampling Frame

Answer 21

The source material from which a sample is drawn

Question 22

Target Population

Answer 22

• the group of people the research is interested in
• the group of people from whom a sample is drawn
• the group of people about whome generalisations can be made

Question 23

Bias

Answer 23

a systematic distortion

Question 24

Generalisation

Answer 24

applying the findings of a particular study to the target population

Question 25

Event Sampling

Answer 25

Where participants are observed by the psychologists who record specific behvaiours (events) each time i occurs to create a total score

Question 26

Time Sampling

Answer 26

When psychologists observe and record behaviour at specific time intervals - creates an average score of behaviour E.g every 15 minutes

Question 27

Observational Sampling Techniques

Answer 27

Used to collect data about specific behaviours or events within specific time frames