Practical skills

• Define 'random error'

  Unpredictable variation between measurements that leads to a spread of values about the true value
• How can we reduce random error?

  By taking repeat measurements
• Does random error affect accuracy or precision?

  Precision
• Define 'systematic error'

  Causes all readings to differ from the true value by a fixed amount
• How can we reduce systematic error?

  A different technique or apparatus should be used
• Does systematic error affect accuracy or precision?

  Accuracy
• Define 'accuracy'

  A measure of how close a measurement is to the true value
• Define 'precision'

  A measure of how close a measurement is to the mean value. It only gives an indication of the magnitude of random errors, not how close data is to the true value.
• Define 'resolution'

  The smallest change in a quantity that causes a visible change in the reading that a measuring instrument records
• Define 'repeatable'

  The same experiment can repeat a measurement using the same method and equipment and obtain the same value
• Define 'reproducible'

  An experiment can be repeated by a different experimenter using a different method and different apparatus, and still obtain the same results
• Define 'uncertainty'

  The interval that a value is said to lie within, with a given level of confidence