inferential statistics

• Unrelated design

  independent groups
• Related design

  repeated measures and matched pairs
• Nominal data

  qualitative data, labels (hair colour/male and female)
• Ordinal data

  data that can be ranked and ordered
• Interval data

  measured along a scale, numerical values
• Type 1 error

  occurs if the investigator rejects a null hypothesis that is actually true in the population
• Type 2 error

  occurs if the investigator fails to reject a null hypothesis that is actually false in the population
• What is a unrelated design using nominal data

  Chi-squared
• What is a related design using nominal data

  Sign test
• What is a test of correlation using nominal data

  Chi-squared
• What is a unrelated design using ordinal data

  Mann-Whitney
• What is a related design using ordinal data

  Wilcoxon
• What is a test of correlation using ordinal data

  Spearman's rho
• What is a unrelated design using interval data

  Unrelated t-test
• What is a related design using interval data

  Related t-test
• What is a test of correlation using interval data

  Pearson's R
• The sign test

  test of difference , repeated measures , nominal data
• Level of significance / probability

  0.05

  the level at which a researcher decides that the findings are significant and will reject the null hypothesis
• Directional hypothesis

  states the direction of the relationship

  (eg. boys are more helpful than girls)
• Non-directional hypothesis

  does not predict the direction of the difference or relationship

  (eg. girls and boys are different in terms of helpfulness)
• Critical value

  critical value table

  - the significance value (0.05)

  - the number of participants in the investigation (N)

  -whether the hypothesis is directional or non-directional
• Significance levels

  if the calculated value is more than the critical value the difference is not significant