Mann Whitney U test

• Example Q


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• Formula for Mann Whitney


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• Steps of Mann U Whitney test


  1. rank all scores TOGETHER (put in order from lowest to highest + assign ranks e.g. lowest No = 1 - for any of same value add ranks together + divide by 2)
  2. add up all the ranks for condition/column 1 to get R1 (rank 1) + add up all the ranks for column 2 to get R2 (rank 2)
  3. use formula to calculate
  4. the observed value is the smaller number
  5. if observed value is less than critical value, results = significant
• Example Q using source from before

  How to rank data:

  
• To read critical values table for Mann U Whitney test we need to know:


  -the level of significance

  -the number of Ps in each condition
• Example Q: Explain how you would read a critical values table from this Mann U Whitney test (2)


  to find the critical value in this study I would take the number of Ps in condition 1 (6) and the number of Ps in condition 2 (6) and find where they meet in the table at the 0.05 level of significance
• Example answer 


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• What must a significant statement include

  • compare the observed value and the critical value
  • indicate if the results are significant or not at the 0.05 level of significance (referring to N1 + N2)
  • indicate which hypothesis we would accept (and outline this) and which we will reject

  CONTEXT
• Example Q


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• What to include in a conclusion for a stats test


  • indicate if the results are significant/not significant in context, referring to p value
  • make a suggestion
  • make an inference (this could be because...)
  • state which hypothesis we will reject/accept
• Example Q


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