Flashcards in 2.3.1 Participants & Probability sampling Deck (20):
what is a target population?
a group of people sharing a set of characteristics about which the researcher wishes to draw conclusions
in a study to investigate whether children aged 5 - 11 watch to much tv who is the target population?
children aged 5 - 11
in an ideal world who would you study?
everyone in your target population
why is it not possible to carry out research on everyone in your target population?
target population is often too large
instead of studying the entire population who do we look at?
a small representative sample
why is it important the sample is representative of the target population?
do it is a true reflection and you are able to generalise
when deciding sample size what do you need to consider?
what is sampling?
how participants are selected for research studies
what is probability sampling?
all the individuals in the target population have an equal chance of being selected
what is a sampling frame?
a complete list of the target population from which you can draw your sample
give examples of sampling frames:
registers - school, work, births, marriages
what is random sampling?
each person in a given population stands an equal chance of being selected
what is a strength of random sampling?
laws of probability predict it is the best chance of gaining a representative sample
one weakness of random sampling is that a representative sample isn't guaranteed, why?
accidental bias - e.g. all boys selected
weaknesses of random sampling - what three reasons can make it hard to obtain a random sample?
1. cant get a list of everyone in target population
2. cant contact everyone randomly selected
3. those selected may refuse to participate
what is systematic random sampling?
researcher randomly selects the first participant in the population and then selects each nth participant from the list
what is stratified sampling?
target population divided into sub categories
participants randomly selected within each sub category in the proportion they occur in the population
(stratified sampling) if 2.5% of British people are of Indian origin, how many in your sample will be randomly selected from people of British Indian origin?
what is the most representative probability sampling method?