Unit 3 experimentation Flashcards
Accuracy
The degree of closeness to the true actual value
Box Plot
Graph showing a data set arranged into numerical order and divided into quartiles (25% of data)
Causation
A link between variables in which one variable is know to be directly affecting the other
Confounding variables
Factors that influencce the results of an experiement and cause mistaken associations between the independent variable and dependent
Continuous variable
Variable that can be measured and for which infinite values exist
Correlation
A relationship beyween 2 variables that does not imply causation
Dependent variable
variable that is measured
Discrete variable
variable that must fall into clear cut categories
Error bar
Line through a data point drawn parallel to an axis showing variation in the data for that point or the extent of the data for which there is a 95% expectation that the true mean lies along it
In vitro
Experimental procedure carried out in lab conditions using parts of organisms such as cells or tissues
In vivo
Procedures carried out in lab or field conditions using entire living organisms
Independent data sets
Repeated data sets that are collected in different labsby different workers and at different times but under the same general conditions
Independent variable
Experimental variable that is purposely altered by the investigator
Line of best fit
Straight line drawn through a scatter plot that indicated the trend shown by the data
Mean
Add induvidual data items up and divide by number of data sets
average
Mode
Most common value in the data set
Multifactorial
Experiement that has more than one dependent variable
usually more complex
Negative control
an experiemental aspect in which the independent variable is set at 0 or at no treatment with the aim of producing a negative result
Observational studies
Work that is usually carried out in the field in vivo snd usually produces qualitative data (descriptive)
Pilot study
A small-scale study conducted to refine values for independent and controlled variables prior to conducting an experiment
Placebos
Negative controls used in drug and vaccine trials that do not contain the active ingredient being treated
Positive control
An experiemntal aspect set up to show that a system is capable of detecting a positive result should it occur
Precision
The closeness of repeated measurements of a variable
Qualitative data
Data with descriptive values
Quantitative data
Data that have numerical values
Random sampling
Sampling in such a way as to ensure that all induviduals have an equal chance of being selected in order to obtain a statistically representative sample
Randomised block design
Experimental protocol in which that effects of potentially confounding variables can be reduced
Range
The difference between the two extremes of a set of numerical data
Ranked data
Data that has been transformed into arbitary (no pattern/ reason) groups
Reliability
The degree of confidence that an experiemntal procedure can produce consistent values
Representative sample
A sample that shares the same mean and same degree of variation about the mean as the population as a whole
Standard deviation
Value given for the spread or variation in data
Standard error of the mean
value for the standard deviation of sample means to the overall mean of a data set
Stratified sampling
Dividing a population into groups or strata before carrying out the sampling to take account of perceived differences in the induviduals such as size or age
Systematic sampling
sampling at regular intervals in space or time to take account of a gradient such as a slop tidal cycle or seasonal changes
Validity
Refers to the control variables to produce fair testing
Variable
Factor in an experiment that is changable or can change
