3.2 Experimentation Flashcards
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
Reliable = Repeats
Accuracy
Data or sets of data that are close to the true value
Precision
Measured values are close to one another
What is a pilot study
A small scale version of a larger study
What is the purpose of a piolet study
Establish the appropriate techniques and number of repeats required
Ensure an appropriate range of value for the independent variable
What is discrete variation
Where measurement fall into distinct groups
What is continuous variation
Characteristic will have a range of values between a minimum and a maximum
What is a simple experiment
One independent variable
What is a multifactorial experiment
More than one independent variable
What is a observational experiment
A study in which the investigator simply observes and does not change the independent variable
What is correlation
When there is a relationship between 2 variables
When is causation implied
When the changes in the values of the independent variable are known to cause changes in the dependant variable
What is a confounding variable
A variable other than the independent variable that can affect the experiment and must be kept constant
What is a randomised block trial
When blocks of treatment and control groups can be distributed in such a way that any influence confounding variables have in likely to be the same across the entire study
What is a negative control
Provides results in the absence of treatment
What is a positive control
A treatment that is included to ensure the system can detect a positive result
Where are placebos mostly used
In human drug trials as a negative control
Why are placebos effective
They show a measurable change in the dependant variable as a result of the patients expectations
What is a double blind trial
Neither the patient nor the researcher is aware of who has been administered the placebo
What is In Vitro
Techniques performed outside of a living organism
What is In Vivo
Refers to an experiment using a whole living organism
What is representative sampling
Should share the same mean and variation of the population as a whole
What is random sampling
Members of public have an equal chance of being selected
What is systematic sampling
Member of population selected at regular intervals
What is stratified sampling
Population divided into categories and then sampled proportionately
What is an independent replicate
Carried out to produce independent data sets
Qualitative data
Using your senses to observe results
Quantitative data
Measure with numerical data
Error Bars
Graphical representations of the variability of data
