Key practical terms Flashcards
Accurate
Results that are close to the true mean
Anomaly
A result that doesn’t fit the pattern
Calibration
Marking a scale on a measuring instrument. For example placing a thermometer in melting ice to see whether it reads zero, in order to check if it has been calibrated properly
Categoric
Variables that are labels eg. colour of cats
Continuous
Variables that can be any number
Control
The variables you need to keep the same so your results are meaningful
Dependant
The variable you measure (and out into the results table)
Hypothesis
A proposal intended to explain the certain facts or observations
Independent
The one variable you change in an experiment
Measurement error
The difference between a measured value and the true value
Precise
Results that are close together (but not necessarily right!). There is very little spread about the mean value.
Range
The maximum and minimum values for the independent or dependent variables eg from 10cm to 50cm
Repeatable
You do the experiment again and get the same results
Reproducible
The experiment is done by someone else and gets the same results
Resolution
The smaller the scale on a measuring instrument (eg thermometer, measure cylinder) the greater the resolution
Systematic error
These cause readings to differ from the true value by a consistent amount each time a measurement is made. Sources of systematic error include the environment, methods of observation or instruments used. These cannot be dealt with by simple repeats
Uncertainty
The interval within which the true value can be expected to lie. Uncertainty can be expressed in terms of the spread of value obtained. For example, a length of 56cm ± 2cm would mean the true value could be anywhere between 54cm and 58 cm
Why we do repeats
To reduce the effect of random error on a mean
