P3 - Fieldwork

• Define reliability.

  The extent to which your investigation produced consistent results.
• What is quantative data?


  Data which provides a numerical value.
• What statistical tests can be carried out on quantative data?


  Mean, median, mode, range.
• Define random sampling.


  Random sampling - involves choosing sites at random, may use random number generator. Used with large sample populations to avoid bias, however can lead to poor representation of overall sample.
• Define stratified sampling.


  Stratified sampling - deliberately introducing bias to a sample.
• Define systematic sampling.


  Systematic sampling - working to a system to collect data, e.g taking sample every 50m across a river.
• What is a line graph?


  A line graph summarises how two pieces of data are related - represent continuous data.
• What does a bar chart show?


  A bar chart can show discontinuous data where simple bars are used to present data.
• How is a proportional symbol map used?


  Symbols are located on a map to represent data and are proportional to the value of the data.
• What is a pie chart?


  A pie chart shows relative size of different parts which make up a total.
• What is a scatter graph?


  Shows the relationship between two variables with a line of best fit.