Unit 3 Flashcards
Replacement
The use of animals should be replaced with alternatives as often as possible
Reduction
The number of animals used in a study should be reduced as much as possible.
Refinement
For those animals being used, the negative impact on them should be minimised.
Validity
Variables are CONTROLLED, so that any measured effect is likely to be due to the independent variable.
Reliability
Consistent values in repeats and replicates
Accuracy
Data, or means of data sets, are close to the true value
Precision
Measured values are close to each other. The results show little variation.
Independent variable
The variable that is being changed in a scientific experiment.
Dependent variable
The variable being measured in a scientific experiment.
Discrete
Finite values that allow placement into separate groups.
Continuous
Values change gradually from one extreme to another.
Confounding variable
A confounding variable is a variable, other than the independent variable, that may affect the values of the dependent variable.
Negative control
Provides results for what happens in the absence of a treatment.
(i.e. doesn’t include the independent variable)
Positive control
A positive control is included to check that the system can detect a positive result when it occurs.
Placebo effect
The placebo effect is a measurable change in the dependent variable, as a result of the PATIENTS EXPECTATIONS, rather than changes in the independent variable.
In Vitro
In vitro refers to the technique of performing a given procedure in a controlled environment OUTSIDE of a living organism.
E.g. cells growing in a culture medium
In Vivo
In vivo, refers to experimentation using a whole, living organism.
Random sampling
In random sampling, members of a population have an equal chance of being selected.
Systematic sampling
In systematic sampling, members of a population are selected at regular intervals.
Stratified sampling
In stratified sampling, the population is divided into categories that are sampled proportionally.
Representative sample
A representative sample should share the same mean and the same degree of variation about the mean as the population as a whole.
Qualitative data
Subjective and descriptive
Difficult to analyse, and difficult to measure directly
Quantitative data
Measured objectively, usually with a numerical value
Measured directly
Ranked data
Data is sorted in order of magnitude
E.g. data is sorted from low to high
Correlation
Correlation exists if there is a relationship between 2 variables.
Positive correlation
When one variable increases, then the other variable increases too
Negative correlation
When an increase in one variable is accompanied by a decrease to the other.
Review Articles
Summarise current knowledge and recent findings in a particular field
Peer Review
Where specialists with expertise in the relevant field asses the scientific quality of a submitted manuscript and make recommendations regarding its suitability for publication.
Ethics in human studies
Informed consent
The right to withdraw data
Confidentiality
Pilot study
Used to help plan procedures, asses validity and check techniques
Randomised block design
Where confounding variables cannot be controlled, a randomised block design could be used.
