inferential statistics

• 5% level balances out the risk of making type 1 errors and type 2 errors
• type 1 error is when the psychologist accepts the experimental hypothesis and rejects the null hypothesis when the results were actually due to chance
• type 2 error is when the psychologist accepts the null hypothesis and rejects the experimental hypothesis when the results were actually due to the IV
• interval data- numbers on a fixed scale
• ordinal data- rankings/ratings
• nominal data- categories
• nominal, test of difference, unrelated

  chi- squared
• nominal, test of difference, related

  sign test
• ordinal, test of difference, unrelated

  mann-whitney
• ordinal, test of difference, related

  wilcoxon
• ordinal, relationship

  spearman’s rho
• interval, test of difference, unrelated

  unrelated t-test
• interval, test of difference, related

  related t-test
• interval, relationship

  pearson’s r
• using critical value tables

  1. one tailed/ two tailed
  2. number of participants (N)
  3. level of significance (p<0.05)
  4. whether the calculated value is greater than/smaller than or equal to the critical value