Scientific Method Flashcards
(19 cards)
Sampling
Procedure by which some members of a given population are selected as representatives of the entire populate
Random sampling
Equal chance of being selected out of the population
Stratified sampling
The population is sub-divided into groups and sampling is done from each group
Biased sample
When the general population isn’t represented
Systematic error
causes a consistent positive or negative offset from the ‘true’ value in a set of data, gives same error throughout experiment
Example of systematic error
Ruler being a few CM of each time
Random error
Varies and is equally likely to be positive or negative and may detected by repeated experiments
Example of a random error
Hitting a stopwatch too slow or fast
Accuracy
Refers to how close the measurements are to the true value
If a result is accurate it is
Free from a systematic error
Precision
How close the values are to each other, how similar the measurements are
Quantitative data
Measurements of observations using numbers
Qualitative data
Comparison of observations using words
In a graph
Independent variable goes on the bottom, dependent variable goes on the side
In a table
Independent variable goes on the left, dependent variable on the right
Placebo
Inactive substance or process that mimics the experimental variable but has not effect
Ethical standards for testing on humans
Voluntary participation, informed consent, risk of harm (minimised), confidentiality, anomymity
Ethical standard for testing on animals
Replace use of animals if possible, reduce amount of animals tested, refine process so animals aren’t stressed or harmed for no reason
Percentage change
(New value-Old value)
X100
Old value
