Literature Review and Study Design Flashcards
What is a research question?
A research question provides focus for an investigation
-defines an area of interest
fundamental core of any research project
What are the five key points for a good research question?
- Feasible
- Interesting
- Novel
- Ethical
- Relevant
What is a hypothesis?
A hypothesis should describe what you expect to happen in your study
provides a reference point for study design
reference point for discussion
What is a null hypothesis?
states nothing will happen, that there will NOT be an effect.
* e.g.: There is no difference in owner reported aggression between castrated and uncastrated dogs.
What is an alternate hypothesis?
states what you expect to happen, that there WILL be an effect.
* e.g.: There is an increased incidence of owner reported aggression in uncastrated dogs compared to castrated dogs.
What is a two-sided hypothesis?
There is a difference between group means (either increase or decrease)
What is a one-sided hypothesis?
There is a difference between group means in a given direction.
* Only used if there is some theoretical reason why any differences could be in one direction.
What is the population?
Complete set of people with specified characteristics
What is the ‘target population’ ?
Clinical and demographic characteristics define the target population
What defines the accessible population?
Geographical and temporal characteristics define the accessible population
What is the intended study sample?
is the subset of the
accessible population that is sought to be included
in the study
What is the actual study sample?
is the group of subjects
that do participate in the study
What is random sampling?
The population & sample size is defined
» Population must be larger than the sample size required
What is the benefit of random sampling?
Good validity of generalising the findings from a sample to a population
What is systematic sampling?
Resembles a simple random sample by enumerating the population but then the
sample is selected by a preordained periodic process
What is stratified sampling?
Divide the population into subgroups according to characteristics
* Sex
* Age
* Severity of clinical characteristics
» Take a random sample from each of these strata
What is proprtionate stratified sampling?
Number of subjects selected depends on size of strat
What is disproprtionate stratified sampling?
Equal number of subjects from each strata irrespective of size of
each strata.
What is cluster sampling?
A random sample of natural groupings (clusters) of individuals within the population
» Useful when the population is large and widely dispersed
What are the multiple stages of cluster sampling?
Random sample of pig farms
* Random sample of pens within each pig farm
* Radom sample of individuals from each pig pen selected
What is the definition of inclusion criteria?
These define the main characteristics
of the target population that pertain to
the research question.
* All subjects must fulfill these
requirements to enter the study.
What is the definition of exclusion criteria?
reasons why a
subject should not be enrolled in a study.
» For example:
* High likelihood of being lost to follow-up
* High risk of side effects
* Characteristics that make it unethical to
withhold additional treatment
What are the two main goals of recruting subjects into a study?
Recruit a sample that represents the target population
* Minimise the prospect of getting the wrong answer due to systematic error (bias).
» Recruit a sufficient sample size
* Minimise the chance of getting the wrong answer due to random error (chance).
