Measurements and uncertainties

• Random error is unpredictable

  Will Affect the gradient of the graph

  To reduce affect we take multiple measurements
• Systematic errors will affect all errors by the same amount

  Will not affect gradient but displace it

  examples include zero error or parallax error
• Percentage uncertainty = Absolute uncertainty/True Value * 100
• Accuracy

  How close the value is to the true value
• Precision

  How close results are to each other
• Percentage uncertainty of a gradient

  Percentage uncertainty of a gradient = (best gradient - worst gradient/ best gradient) *100
• Absolute uncertainty from a dataset

  1/2 * range
• Absolute uncertainty of a device

  smallest scale measurement
• Percentage uncertainty equation

  Absolute uncertainty/True Value * 100
• When adding or subtracting uncertainties

  We add the absolute uncertainties
• When multiplying or dividing uncertainties

  We add the percentage uncertainties
• For Powers in uncertainties

  We multiply the power by the percentage uncertainty