Unit 3 - All Key Areas Flashcards
Scientific Cycle
1) observation, 2) construction of a testable hypothesis, 3) experimental design, 4) gathering, recording, analysis of data, 5) evaluation of results, 6) conclusions , 7) the formation of new hypotheses where necessary.
Null Hypothesis
is a hypothesis that says there is no statistical significance between the two variables.
Refine, Reduce, Replace
Three Rs of animal studies
Refine
Ensuring competence in the experimental technique by reducing human error
Reduce
Using fewer animals in an animal study
Replace
Using a different type of animal in an animal study
Peer review
Most scientific publications use peer review. Specialists with expertise in the relevant field assess the scientific quality of a submitted manuscript and make recommendations regarding its suitability for publication.
Pilot Study
1.to develop and/or practice protocols in order to 2.ensure validity of experimental design, 3.check effectiveness of techniques, 4.find a suitable range of values for 5.identify and control confounding variables, 6.identifying suitable numbers of the independent variable, 7. to check whether results can be produced in a suitable time frame.
Independent variable
Variable that is changed in a scientific experiment
Dependent variable
Variable being tested and measured in a scientific experiment
Confounding variable
Variable besides the independent variable that may affect the dependent variable
Distinct variable
Variables that are specific and unrelated to each other
Continuous variable
Variables that have a range of values
Quantitative data
Data that is measured (eg numbers)
Qualitative data
Data that is observed (eg colour)
Ranked data
Observations put into an order from smallest to largest
Parasite load
A measure of the number of parasite found within a host organism
Positive control
Treatment that is included to check that the system can detect a positive result when it occurs
Negative control
Provides results in the absence of a treatment
Precision
The closeness of repeated measurements to one another
Accuracy
Data, or means of data sets, are close to the true value.
Validity
Variables controlled so that any measured effect is likely to be due to the independent variable.
Reliability
Consistent values in repeats and independent replicates.
Multifactorial
Name given to an experiment which has more than one independent variable
In vitro
An investigation carried out using biological molecules or cells out with their normal biological system, e.g. cell culture
In vivo
An investigation carried out using a living organism, e.g. mouse model organism.
Correlation
When two variables seem to be connected
Causation
When changing the independent variable causes the effect noted in the dependent variable
Informed consent, withdraw at any time, confidentiality
Ethical considerations when using human subjects in studies (3)
Science is
the gathering and organisation of testable and reproducible knowledge.
Failure to find an effect (ie a negative result}
is a valid finding, as long as an experiment is well designed
scientific knowledge
can be thought of as the current best explanation which may then be updated after evaluation of further experimental evidence.
Conflicting data or conclusions
can be resolved through careful evaluation or can lead to further, more creative, experimentation.
One-off results
are treated with caution.
Scientific ideas only become accepted
once they have been checked independently.
The importance of publication of methods, data, analysis and conclusions in scientific reports
so that others are able to repeat an experiment
Common methods of sharing original scientific findings include
seminars, conference talks and posters and publishing in academic journals.
The importance of peer review and critical evaluation
So that specialists with expertise in the relevant field assess the scientific quality of a submitted manuscript and make recommendations regarding its suitability for publication.
The use of review articles,
to summarise current knowledge and recent findings in a particular field
Critical evaluation of science coverage in the wider media
to increasing the public understanding of science and to highlight the issue of misrepresentation of science in the media.
Importance of integrity and honesty
the unbiased presentation of results, citing and providing references, avoiding plagiarism.
The replication of experiments by others reduces
the opportunity for dishonesty or the deliberate misuse of science.
plagiarism.
the practice of taking someone else’s work or ideas and passing them off as one’s own
Avoiding plagiarism by
the requirement to cite and supply references.
Ethics In human studies state that
participants must be given Informed consent, the right to withdraw data and confidentiality.
The justification for scientific research include that
- the value or quality of science investigations must be justifiable in terms of the benefits of its outcome including the pursuit of scientific knowledge. 2. The risk to and safety of subject species, individuals, investigators and the environment must be taken into account.
Legislation
- requires that many areas of scientific research are highly regulated and licensed by governments. 2. limits the potential for the misuse of studies and data.
These confounding variables must be
held constant if possible, or at least monitored so that their effect on the results can be accounted for in the analysis.
In cases where confounding variables cannot easily be controlled,
blocks of experimental and control groups can be distributed in such a way that the influence of any confounding variable is likely to be the same across the experimental and control groups.
The control of laboratory conditions
allows simple experiments to be conducted more easily than in the field.
Experiments conducted in vivo tend to be
more complex than those in vitro.
Drawback of a simple experiment is
that its findings may not be applicable to a wider setting
Observational studies
where Investigators may wish to use groups that already exist, so there is no truly independent variable.
These ‘observational’ studies are
good at detecting correlation but, as they do not directly test the model, they are less useful for determining causation.
Reason for sampling
where it is impractical to measure every individual
Sample size is determined by
the extent of the natural variation within a population.
A representative sample should share the same
mean and the same degree of variation about the mean as the population as a whole.
In random sampling,
members of the population have an equal chance of being selected.
In systematic sampling,
members of a population are selected at regular intervals
In stratified sampling,
the population is divided into categories that are then sampled proportionally.
Placebos
Placebos can be included as a treatment without the presence of the independent variable being investigated.
Placebo effect
Placebo effect is a measurable change in the dependent variable as a result of a patient’s expectations, rather than changes in the independent variable
Use of box plots
to show variation within and between data sets
Correlation
Correlation is an association and does not imply causation
Positive correlations
correlation exists when an increase in one variable is accompanied by an increase in the other variable.
A negative correlation
exists when an increase in one variable is accompanied by a decrease in the other variable.
Strength of correlation
is proportional to spread of values from line of best fit.
