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28 Cards in this Set
- Front
- Back
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Accuracy
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An accurate measurement is one which is CLOSE TO THE TRUE VALUE
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Anomalous Data
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Data which falls OUTSIDE THE NORMAL OR EXPECTED RANGE OF MEASURED VALUES. More readings = easier to sport anomalous data
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Calibration
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Involves FIXING KNOWN POINTS and constructing a SCALE between these fixed points
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Causal Link
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A change in ONE VARIABLE that results from, or is caused by a CHANGE in another variable
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Confounding (AKA Control) Variable
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May AFFECT THE OUTCOME OF THE INVESTIGATION
Must be kept CONSTANT or the test will NOT BE FAIR When it is not possible to keep these variables constant, they should be MONITORED |
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Control Experiment
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That which is set up to ELIMINATE CERTAIN POSSIBILITIES
In a well designed investigation, the independent variable is changed and all confounding variables are kept constant. However, something else other than the independent bariable might have produced the results that were obtained. A control experiment is one that is designed to eliminate this possibility |
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Control Group
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A group that is treated in exactly the same way as the experimental group EXCEPT FOR THE FACTOR THAT IS BEING INVESTIGATED. This allows COMPARISON and ensures the data that are collected are VALID
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Correlation
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Shows that there is a RELATIONSHIP BETWEEN TWO VARIABLES, however, might NOT be a causal one
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Dependent Variable
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The variable the value of which is MEASURED for each change in the INDEPENDENT VARIABLE
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Double-Blind Trial
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Used when ASSESSING the EFFECTS OF A NEW TRUG or TREATMENT on HUMANS
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Errors
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Cause readings to be DIFFERENT from the TRUE VALUE
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Evidence
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The DATA or OBSERVATIONS that are used to SUPPORT A GIVEN HYPOTHESIS OR BELIEF
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Fair Test
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A test which ONLY the INDEPENDENT VARIABLE has been allowed to AFFECT the DEPENDENT VARIABLE, can be achieved by keeping all other variables CONSTANT or CONTROLLED
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Hypothesis (AKA Experimental Hypothesis)
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A POSSIBLE EXPLANATION of a problem that can be TESTED EXPERIMENTALLY
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Independent Variable
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The variable for which the VALUES are CHANGED by the investigator
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Null Hypothesis
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A STATISTICAL TEST requires a clear HYPOTHESIS. It can be difficult to PREDICT what would happen as the RESULT of an investigation. It is easier to phrase a HYPOTHESIS in terms of there being no DIFFERENCE or no ASSOCIATION. This is a NULL HYPOTHESIS. As the result of carrying out a statistical test, a decision can eb made about whether to accept or reject this null hypothesis
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Placebo
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A dummy pull given to members of a CONTROL GROUP in medical trials. Ensures the data collcted from a trial are VALID
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Precision
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Related to the SMALLEST SCALE DIVISION on the measureing instrument that is being used
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Probability
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The LIKELIHOOD of an event occuring. Chance is random, probability can be expressed mathematically.
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Protocol
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Once an experiment is shown to produce VALID and RELIABLE results, in becomes a protocol used by other scientists
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Random Distribution
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One that arises as a RESULT OF CHANCE
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Random Errors
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Errors that occur in an UNPREDICTABLE WAY. May be human error, technique or faulty equipment
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Raw Data
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Instrument readings and other data collected at the TIME OF THE INVESTIGATION. The data may be used to calculate percentages and standard deviateions later on
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Reliability
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Something is reliable if it can be REPEATED. If others get the same results, the initial investigation are more likely to be RELIABLE. Reliability can be IMPROVED by carrying out REPEAT MEASUREMENTS
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Systematic Errors
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Errors that cause readings to be SPREAD ABOUT SOME OTHER VALUE than the TRUE VALUE. The readings are all shifted in one diretion form the true value. May occur when using a WRONGLY CALIBRATED instrument
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True Value
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The ACCURATE VALUE which would be find if the quantity could be measured WITHOUT ANY ERRORS
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Validity
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Data is VALID if the measurements are affected by the INDIPENDENT VARIABLE ONLY Also invalid if the CONTROL VARIABLES have been allowed to change.
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Zero Errors
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Caused by INSTRUMENTS that have an INCORRECT ZERO
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