Inferential statistics

• When is Spearman's Rank used?


  Trying to find correlation between 2 co-variables. Data collected has to be ordinal, interval or ratio.
• In which tests does the OV have to be higher or equal to CV in order to be significant?


  Spearman's rank & Chi-squared
• In which tests does OV have to be equal to or lower than CV in order to be significant?


  Mann Whitney, Sign test & Wilcoxon
• When is Mann Whitney U used?


  Test of difference, independent groups, data at least ordinal.
• When is Wilcoxon used?

  Test of difference, data ordinal, interval or ratio, repeated measures design.
• When is sign test used?


  Test of difference, repeated measures design & nominal data.
• When is chi-squared used?


  Nominal data, test of difference (& association) & independent groups.
• Which type of hypothesis is a 2-tailed test?


  Non-directional
• What is the critical value?


  Number a test statistic must reach in order for null hypothesis to be rejected.