Working Scientifically Terms Flashcards
Accuracy
How close a measurement is to the true value.
Do everything you can to minimise errors
Precision
The closeness of agreement between repeats.
(A measurement is ‘precise’ if the values are clustered closely together (around the mean value).
Also, fine measurements (mm) are more precise than large measurements (cm))
Fair Test
Where the only thing affecting your dependany variable is your independant variable.
(Control all other variables)
Repeatability
A measurement is ‘repeatable’ when the SAME person repeats the experiment (using the same method and equipment) and it gives the SAME (or similar results)
(Compare your own repeat readings or compare with another group)
Reproducability
A measure is ‘reproducible if ANOTHER person (or the same person using DIFFERENT equipment/method) can get the SAME or similar results.
(Compare your results to a group with a different method or different equipment)
Validity
How useful your evidence is to actually answer the question.
Make sure your experiment tests the right thing and is a fair test
Resolution
The smallest preceptible change if a measuring instrument reading e.g ± 1°C for a typical mercury thermometer but ± 0.1°C for a typical digital thermometer.
Independant Variable
The variable you CHANGE to see what happens
Put it in the first column if your table, plot in your x-axis
Dependant Variable
The variable you MEASURE.
Plot it on your y-axis
Control Variable
A variable that must be kept the SAME (or at least monitored) to prevent it affecting your results.
(Controlling variables will help make a FAIR TEST)
Continuous Variable
Data that can have a value (“quantity”) anyhwere on a cintinuum between two extremes. These values can either be COUNTED (e.g number of shrimp) or MEASURED (e.g temperature).
Categoric Variable
These variables have values that are LABELS, e.g names of plants or types of material.
(Draw a bar chart)
Uncertainty
The inverval within which the true value can be expected to lie.
(Random error and sytematic error contribute to uncertainty. Typically the uncertainty might be estimated as ± half the smallest scale division)
Measurement Error
The difference between a measured value and the true value.
‘Error’ does not mean ‘mistake’
Random Error
Measurement error due to unpredictable variation from one reading to the next.
(Do your best to control variables. Take repeats and calculate a mean)