Week 4 - Ethics and Participants Flashcards
the aggregate of persons or objects that meet a specified set of criteria, and to whom we wish to generalize results of a study.
population
a subgroup of the population. serves as the reference group to estimate characteristics of and to draw conclusions about the population.
sample
overall group to which findings will be generalized
target population
persons who have an actual chance to be selected, who are available
accessible population
derived from the accessible population
sample
the primary traits of the target and accessible populations that will make someone eligible to be a participant.
inclusion criteria
factors that would preclude someone from being a subject.
exclusion criteria
offer each respondent an equal probability or chance at being included in the sample. they are considered to be: objective, empirical, scientific, quantitative, representative
probability samples
relies on the researcher selecting the respondents. they are considered to be: interpretivist, subjective, not scientific, qualitative, unrepresentative
non probability sample
Name 4 types of probability sampling.
- simple random sampling
- systematic sampling
- stratified random sampling
- cluster sampling
- involves selecting anybody from the accessible population entirely at random.
- each person within the population has an equal chance of being selected.
- a full list of everyone within a sample frame is required.
- random number tables or a computer is then used to select respondents at random from the list.
random sampling
every subset of a specified size n from the population has an equal chance of being selected.
simple random sample
assumes that the population is randomly ordered.
systematic random sampling
Describe the procedure for systematic random sampling.
- number units in population from 1 to N.
- decide on the n that you want or need.
- N/n = k the interval size.
- randomly select a number from 1 to k.
- take every kth unit.
-is possible when it makes sense to partition the population into groups based on a factor that may influence the variable that is being measured.
stratified random sampling
groups within the population that have been created based on a specific factor
strata/stratum
When does stratified sampling work best?
when a heterogeneous population is split into fairly homogenous groups.
if sampling fraction is equal for each stratum
proportionate stratified random sampling
unequal sampling fraction in each stratum
disproportionate stratified random sampling
Describe cluster random sampling.
- divide the population into groups (clusters).
- obtain a simple random sample from all possible clusters.
- obtain data on every sampling unit in each of the randomly selected clusters.
include all accessible subjects as part of the sample.
consecutive sampling
- involves selecting the nearest and most convenient people to participate in the research.
- not representative and is considered a very unsatisfactory way to conduct research.
convenience sampling
- used when the research is focused on participants with very specific characteristics such as being members of a gang.
- having identified and contacted one gang member, the researcher asks to be put in touch with any friends or associates who are also gang members.
snowball sampling
Name 4 factors affecting power.
- size of the effect
- standard deviation of the characteristic
- bigger sample size
- significance level desired
Name 2 statistical tests used to measure how representative of the whole population the sample data you have collected is.
- standard error
- confidence levels
using the standard deviation of the population and the sample size, a statistical calculation can measure the degree of error likely to occur btwn the results of a sample and the results of a census.
standard error
the ___ the sample, the ____ the standard error.
larger, lower
based on the distribution of the sample
confidence levels
