statistical testing

• what is the role of significance?

  Scientistis try to generlise from their sample to the target population statistical tests identify how likely it is that the results from our sample accuratley reflects what would happen in the population
• what is a Type 1 error?

  When a null hypothesis is rejected when it should have not been meaning the data has been mistakenly interpreted as signifcant
• what is a Type 2 error?

  When a null hypothesis is accepted when it should have not been
• Wilcoxon test

  • is used when an experiment has a repeated measures design
  • must be at least ordinal data
• Wilcoxon test process:

  1. state the alternate hypothesis
  2. place raw data in table
  3. find differences between scores and rank from low to high- lowest is rank 1
  4. calculate the observed value by adding up the ranks and picking the smallest option between negative and positive ranks
  5. find if it is significant
• Man whitney test:

  • data is ordinal
  • independent groups design
• man whitney test process:

  • state alternate hypothesis
  • place raw data in table
  • rank each set of data
  • calculate observed value of U
  • use the smaller value out of a and b
  • find significance