Biology Terminology

Card Set Information

Biology Terminology
2014-04-30 13:41:25
Biology Glossary

AQA Biology Glossary of terms
Show Answers:

  1. Define: Accuracy
    An accurate measurement is one which is close to the true value.
  2. Define: Anomalous data
    Anomalous data are those measurements that fall outside the normal, or expected, range of measured values.
  3. Define: Calibration
    When using a measuring instrument, calibration involves fixing known points and constructing a scale between these fixed points.
  4. Define: Confounding variable
    • A confounding variable is 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.
  5. Define: Control experiment
    An experiment that is set up to eliminate the possibility that something else other than the independent variable might have produced the results that were obtained.
  6. Define: Control group
    • A group that is treated in exactly the same way as the experimental group except for the factor that is being investigated.
    • This allows scientists to make a comparison.
    • It ensures that the data that are collected are 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.
  7. Define: Double-blind trial
    • A trial in which neither participant or researcher is aware of the treatment each participant is receiving 
    • This reduces the effect of bias and increases validity
  8. Define: Evidence
    The data or observations that are used to support a given hypothesis or belief.
  9. Define: Fair test
    • A test in which only the independent variable has been allowed to affect the dependent variable 
    • All other variables have been controlled or kept constant
  10. Define: Precision
    The smallest scale division on the measuring instrument that is being used.
  11. Define: Random distribution
    A random distribution is one that arises as a result of chance
  12. Define: Reliability
    • The results of an investigation may be considered reliable if they can be reproduced in further tests 
    • The reliability of data within a single investigation can be improved by carrying out repeat measurements.
  13. Define: Systematic errors
    • Errors that cause readings to be spread about some value other than the true value.
    • In other words, all the readings are shifted in one direction from the true value.
    • Systematic errors may occur when using a wrongly calibrated instrument.
  14. Define: Validity
    • Data are only valid if the measurements that have been made are affected by a single independent variable only.
    • They are not valid if the investigation is flawed and control variables have been allowed to change or there is observer bias.
    • Conclusions are only valid if they are supported by valid and reliable data measured to an appropriate level of accuracy.
  15. Define: Zero errors
    Errors caused by instruments that have an incorrect zero