ISA Glossary Terms
- Created by: lyd_.jones
- Created on: 29-04-15 21:57
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- ISA Glossary Terms
- Accuracy
- A result is considered "accurate" if it is close to the true value.
- Data
- Information that has been collected .
- Qualitative or quantitative.
- Errors
- Measurement Error
- The difference between a measured value and the true value.
- Anomalies
- Results which are judged not to be part of the variation caused by random uncertainty.
- Random Error
- Cause readings to be spread about the true value, due to results varying in an unpredictable way from one measurement to the next
- Effects can be reduced by making more measuremens and calculating a new mean.
- Systematic Error
- These cause readings to differ from the true value by a consistent amount each time a measurement is made.
- Source of this error could include: environment, methods of observation, or instruments used.
- Cannot be dealt with by simple repeats. If you suspect a systematic error, the experiment should be repeated using a different technique or equipment, Then compare results.
- Zero Error
- Measuring system gives a false reading when the true value of a measured quantity is zero.
- May result in systematic error.
- Eg. the needle of an ammeter failing to return to zero when no current flows.
- Measuring system gives a false reading when the true value of a measured quantity is zero.
- Measurement Error
- Calibration
- Marking a scale on a measuring instrument.
- Eg. Placing a thermometer in melting ice to see whether it reads zero.
- In order to check if it has been calibrated correctly.
- Eg. Placing a thermometer in melting ice to see whether it reads zero.
- Marking a scale on a measuring instrument.
- Evidence
- Data which has been shown to be valid.
- Fair Test
- Only the independent variable is allowed to change the dependent variable
- Hypothesis
- A proposal intended to explain certain facts or observations
- Interval
- Quantity between readings.
- Eg. A set of 11 readings equally spaced over a distance of 1 metre would give an interval of 10cms.
- Quantity between readings.
- Precision
- Very little spread about the mean value.
- Depends on the extent only random errors.
- It gives no indication of how close results are to the true value.
- Prediction
- Statement suggesting what will happen in the future.
- Based on observation, experience or a hypothesis.
- Statement suggesting what will happen in the future.
- Range
- Maximum and minimum values of either variables.
- Important in ensuring a pattern is detected.
- Eg. "From 10cm to 50cm" or "From 50cm to 10cm"
- Maximum and minimum values of either variables.
- Repeatable
- If the original experimenter repeats the exact same investigation and obtains the same results. The measurements are repeatable.
- Reproducible
- If the investigation is repeated by another person using different equipment or techniques but obtains the same results the measurements are reproducible.
- Resolution
- This is the smallest change in the quantity (input) of a measuring instrument
- That gives a perceptible change.
- This is the smallest change in the quantity (input) of a measuring instrument
- Sketch Graph
- A line graph which shows the general shape of the relationship between the variables.
- No points plotted.
- Labelled axes. May not be scaled.
- True Value
- Value that would be obtained in ideal measurement
- Uncertainty
- Interval within which the true value can be expected to lie.
- With a given level of confidence.
- Eg. Th temperature is 20degrees Celsius+2 degreees Celsius. At a level of confidence at 95%
- Interval within which the true value can be expected to lie.
- Validity
- Suitability of the investigative procedure to answer the question being asked.
- Eg. An investigation to find out if the rate of a reaction depended on the concentration of 1 of the reactants would not be a valid procedure if the temperature of the reactants was not controlled.
- Suitability of the investigative procedure to answer the question being asked.
- Valid Conclusion
- A conclusion supported with valid data obtained from an appropriate experiment and based on sound reasoning.
- Variables
- Categoric Variables
- Variables that have values that have labels.
- eg. names of plants or types of material
- Variables that have values that have labels.
- Continuous Variables
- Variables that can have values that can be given a magnitude either by counting or by measurement
- Control Variables
- A variable that has to be kept constant or at least monitored because it can affect the outcome.
- Dependent Variable
- The variable where the value is measured for each and every change in the independent variable.
- Independent Variable
- The variable in which values are changed or selected by the investigator.
- Categoric Variables
- Accuracy
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