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Bias and Precision

Learning outcomes

On watching this video, students should be able to:

  1. Identify bias and precision as the two ways in which a point estimate may differ from the true value of the population parameter. 
  2. Explain how precision refers to the stochastic or random component of variation; that is capture by the sampling distribution of the point estimate (in particular the standard error).
  3. Explain how bias refers to a systematic difference between the true value and the point estimate.
  4. Infer the links between bias and precision and good study design aimed at obtaining unbiased point estimates and maximising precision (through reducing sampling variation).