Sampling!

Question 1

Sampling types

Answer 1

Opportunity sampling
Random sampling
Systematic sampling
Stratified sampling
Volunteer sampling

Question 2

sampling definition

Answer 2

the method used to select participants

Question 3

Opportunity sampling

Answer 3

Recruit those people who are most convenient or most available
Eg people walking by you in the street

str: easiest and least time consuming bc less time to locate sample

lim: biased bc sample is drawn from a small part of the population

Question 4

Random sample

Answer 4

Each item in a population has an equal chance of being selected

Str: unbiased- all members of target pop have equal chance

Lim: Time consuming- need to have a list of all members of pop and contact them all

Question 5

random sample techniques

Answer 5

Lottery method=
1) obtain a list of all ppl in the population
2) put all the names in a lottery barrel or hat
3) select the names required

Random number generator
1) number every member of the population
2) using, for example, Microsoft excel type= RAND(100) to get a random number between 1-100

Random numer table=
1) give every member of pop a number
2) starting position in the table is determuned blidndly by placing finger anywhere

Question 6

Stratified sample

Answer 6

Subgroups within a pop are identified and participants are obtained from each of the strata in the proportion to their occurence in the pop. Selection from the strata is done using a random technique.

Str: Likely to be more rep than other methods bc proportional and representative

Lim: Very time consuming to idently subgroups and randomly select and contact

Question 7

Systematic sample

Answer 7

Use a predetermined system to select participants
eg selecting every nth person from a phonebook
The numerical interval is applied consistently

Str: Unbiased as participants selected from an objective system

Lim: Not truly unbiased unless you select a number using a random method and start w this person and then select every nth person

Question 8

Volunteer sample

Answer 8

Advertise for participants
eg newspaper, noticeboard, internet

str: Gives access to a wide variety of participants which may make the sample more rep

Lim: Volunteer bias: sample is biased in other ways as participasnts are likely to be more motivated or have more time on their hands or theyre broke

Question 9

what is sample bias

Answer 9

bias= a systematic distortion

sample bias= even tho all sampling methods aim to produce a rep sample, they are inevitably biased or distorted

Question 10

what is generalisation

Answer 10

apllying the findings of a particular study to the population