EMPA Flashcards
Accuracy
An accurate measurement is one which is close to the true value.
Anomalous data
Measurements that fall outside the normal, or expected range of measured values.
A large number of readings allows anomalous data to be identified with greater certainty.
Calibration
When using a measuring instrument, calibration involves fixing known points and constructing a scale between these fixed points.
Casual Link
Change in one variable that results from or is caused by a change in another variable.
Chance
Essentially the same as luck. The results of an investigation could have a genuine scientific explanation but they could be due to chance.
Scientists carry out statistical tests to assess the probability of the results of an investigation being due to chance.
Confounding variable
One that may, in addition to the independent variable, affect the outcome of the investigation.
Confounding variables must be kept constant or the investigation will not be a fair test.
Sometimes referred to as control variables.
Control Experiment
An experiment that is set up to eliminate certain possibilities.
used to eliminate possibility that something other than the independent variable might have produced the results obtained.
Control Group
A group treated exactly the same way as the experimental group except for the factor that is being investigated. Allows comparison.
Ensures that data is valid because any differences between the results for the experimental group and those for the control group will be due to a single independent variable.
Correlation
Shows that there is a relationship between two variables, however, it might not be a casual one.
Dependent variable
The variable the value of which is measured for each change in the independent variable.
Double-blind trial
A trial, usually in context of medicine, when assessing the effects of a new drug on humans. Neither the patients nor the scientists concerned know which treatment a particular individual is receiving until after completion of the trial.
Helps avoid bias and increase validity of the trial.
Errors
Errors cause readings to be different from the true value.
Evidence
The data or observations that are used to support a given hypothesis or belief.
Fair Test
A fair test is one in which only the independent variable has been allowed to affect the dependent variable. A fair test can usually be achieved by keeping all other variables constant or controlled.
Hypothesis
Sometimes known as an experimental hypothesis, this is the possible explanation of a problem that can be tested experimentally.