KA 2 Flashcards
What is Validity?
When variables controlled so that any measured effect is likely to be due to the independent variable.
What is Reliability?
Consistent values in repeats and independent replicates.
What is Accuracy?
When data, or means of data sets, are close to the true value.
What is Precision?
When measured values are close to each other.
What is integral to the development of an investigation?
A pilot study
What is a pilot study used to do?
To help plan procedures, assess validity and check techniques.
What does a pilot study allow for?
This allows evaluation and modification of experimental design
The use of a pilot study can ensure?
An appropriate range of values for the independent variable
In addition a pilot study allows the investigator to?
Establish the number of repeat measurements required to give a representative value for each independent datum point
An independent variable is the variable that is?
Changed in a scientific experiment.
A dependent variable is the variable being?
Measured in a scientific experiment. Independent and dependent variables can be continuous or discrete
Experiments involve the manipulation of the?
Independent variable by the investigator
The experimental treatment group is compared to a?
Control group
The control of laboratory conditions allows for?
Simple experiments to be conducted more easily than in the field.
A drawback of a simple experiment is that?
Its findings may not be applicable to a wider setting.
A multifactorial experiment involves?
A combination of more than one independent variable or combination of treatments.
Investigators may use groups that? What does this mean?
Already exist, so there is no truly independent variable
Observational studies are good at detecting? What are they not useful for?
Correlation, but since they do not directly test a hypothesis, they are less useful for determining causation
In observational studies the independent variable is not? Why?
Directly controlled by the investigator, for ethical or logistical reasons.
Due to the complexities of biological systems what may affect the dependent variable?
Other variables besides the independent variable
Confounding variables must be held… if this isn’t possible what else happens?
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, what could be used?
A randomised block design could be used
Randomised blocks of treatment and control groups can be distributed in such a way that the influence of what?
Any confounding variable is likely to be the same across the treatment and control groups.
Control results are used for?
Comparison with the results of treatment groups
The negative control provides results in the?
Absence of a treatment.