wk 2 Flashcards
quantitative research
objective
generates ‘facts’ about human behaviour
aims to explain the data and generate predictions
ideally requires LARGE PROBABILISTIC SAMPLES
uses statistical tests to process numerical data
seeks to discover general laws governing human behaviour -> nomothetic approach
associated with realism
qualitative research
subjective
uncovering the meaning ascribed to individual behaviour
aims to describe the data and generate understanding
often relies on SMALL NON-PROBABILISTIC SAMPLES
uses analytic and conceptual tools as well as data extracts to produce compelling arguments
interested in unique (idiosyncratic) features of single individuals -> idiographic
associated with interpretativism, constructivism and realism
probability sampling
requires each unit in the population to have a KNOWN CHANCE to be selected.
requires a clearly defined population that we can access
types of probability sampling
simple random systematic random stratified cluster multi stage
simple random
each unit has a known and equal chance of being selected.
samples are selected at random using a technique :
lottery method / hat method / table of random numbers
systematic sampling
each unit in a population has a known and equal chance of being selected
samples are selected systematically -> everything Nth unit is selected
✔️ work without a population list if population availability is not an issue
✖️ distribution of the population frame needs to be random
✖️ both simple and systematic random sampling do not yield by default representative samples
stratified
introduces a step before sampling the population to determine the sub-groups.
proportionate / disproportionate stratified sampling depending on whether we apply the same sampling fraction across the sub-groups
✔️ more representative
✖️ all these echinacea can be very time consuming and costly
cluster
selecting clusters that reduce time and costs for accessing sampling units
clustering : only elements in te selected clusters are samples
stratified : elements from all groups are sampled
multi stage
applying random or systematic sampling at several stages of constituting the sample
random selection of one group and further randomising that group.
non probability sampling
the chance for each unit in the population to be selected is NOT KNOWN.
list of units in population is not needed.
used in experimental research
types of non-probabilistic sampling
convenience
purposive
quota
snowball
convenience
(availability / ad libitum)
participants who are available to the researcher - respond to an ad or volunteer
most common
purposive
people who have a particular set of characteristics that are relevant for the study
quota
more representative
an extra step before unit selection / identifying relevant characteristics of the units and the % in the population
apply convenience sampling to fill the quotas
snowball
small/ hard to reach populations with specific characteristics
when serveral sample units are identified we ask each individual to refer a fixed number of persons that fit our selection criteria
ptps recruit new ptps
✔️ reaches hidden populations
✖️ initial individuals will bias the sample