Week eight quiz Flashcards
Define population?
- well-defined group with specific characteristics
- all the individuals the researcher is interested in studying
Define sample?
- subset of overall population
- set of elements that make up population
Define convenience sampling?
-All members of the population with the relevant characteristics who can be readily found (and consent)
Define snowball sampling?
-A participant refers the researcher to more potential participants, who may then refer researcher to further potential participants (snowballing).
Define purposive sampling?
-An intentional (purposeful) approach is made by the researcher to select participants with specific characteristics or participants within a specific area.
Define Quota sampling?
-A sample gathered to represent population as closely as possible e.g. 40% of population is male so try to make sure 40% of sample is male
Define simple random sampling?
-Participants allocated ‘randomly’ to the study or part of a study: ‘pulled out of a hat’ chosen by computer.
Define Stratified random sampling?
-Members of the population allocated to groups according to characteristics important to the study and then subjects randomly chosen from these groups
What are eligibility criteria so important?
-Characteristics specific to allow generalisability of findings
What are the main purposes of sampling?
- Increase efficiency of study
- Maintain representativeness of sample
Name the two MAJOR headings under which sampling falls?
- Probability
- non-probability
What are the advantages of random sampling?
- No researcher bias
- Maximise representativeness
What is the aim of stratified random sampling?
-Increase representativeness
What are the disadvantages of non probability sampling?
- Less rigorous
- Limits generalisability
- Not representative
Name 4 qualitative data collection methods?
-In-depth interviews: may be structured, semi-structured or unstructured
-Focus groups: involve multiple participants discussing an issue
-Secondary data/document review: diaries, written accounts of past events, photographs
-Observations: may be on site, or under ‘laboratory conditions’, for example, where participants are asked to role-play a situation to show what they might do.
How is trustworthiness/rigor assured in qualitative research?
- Credibility (truthfulness)
- Auditability (consistency)
- Transferability (fittingness/applicability)
- Confirmability (no bias or distortion)
Why is rigor so important?
Need to know methods can be trusted and can have confidence in results, and using them ie
applying in clinical practice
List 4 quantiative data collection methods
- Physiologic/laboratory-based: Experiments/clinical trials
- Observational: Observing and recording well-defined events (e.g., counting the number of patients waiting in emergency at specified times of the day)
- Questions & self-report scales- questionnaires: -Administering surveys with closed-ended questions questionnaires
- Interviews: face-to face and telephone interviews
Define reliability and validity in relation to measurement error?
Reliability means: that a measure can be relied upon consistently to give the same result if the aspect being measured has not changed
Validity reflects how accurately the measure yields information about the true or real
variable being measured. A measure is valid if it measures correctly & accurately what it is intended to measure
Descriptive statistics allows researchers to?
describe, organise & summarise raw data
Inferential statistics allows researchers to?
Estimate how reliably they can make predictions & generalise their findings based on the data
The purpose of descriptive statistics is to?
Organize and summarise data
Name four levels of measurement in quantitative data analysis and briefly define each of these:
Nominal: discrete categories
Ordinal: relative ranking
Interval; specific numerical distance between scores- treated as equal; continuous
Ratio: as above but has absolute zero
Name and briefly describe the three most common measures of central tendency?
Mean: most common score
Median: middle score
Mode: average score
Cross-sectional studies collect data…
collect all data at one point in time
Longitudinal studies collect data…
Collect data at different points in time
Retrospective studies collect data…
collect data on past events
Prospective studies collect data…
collect data as they occur
Define independent variable?
-manipulated variable (cause)
used to predict outcome of interest ie dependent variable
Define dependent variable?
measured variable (effect) consequence/presumed effect that changes with change in independent variable
Name two types of validity and briefly define each?
Internal validity: does the independent variable accurately measure what it says it will
measure. Asks whether independent variable really made the difference- refers to
the causal relationship
External validity: deals with problems of generalisability of findings to other populations and other environmental conditions
