collection, organisation and presentation of graphs

• what is the correlation coefficient?

  A statistical measure that describes the size and direction of a relationship between two or more variables
• what is a positive correlation?

  as one variable increases so does the other
• what is a negative correlation?

  as one variable increases the other decreases
• zero correlation is when there is no relationship between the two variables
• causation indicates that a change in one variable is the direct result of a change in the other variable
• what is a control used for?

  to provide a comparison against the actual experiment
• what is statistical uncertainty?

  result of an experimenters inability to take the same measurement the exact way each time
• how can statistical uncertainty be reduced?

  Increasing sample size.
• what is systematic uncertainty?

  a consistent repeatable error usually caused by measuring instruments that are incorrectly calibrated or a defect in the measuring equipment
• what is accuracy?

  how close a measurement is to its true value
• what is precision?

  how the close the measurements are to each other