Inferential Statistics

• Statistical Test : Sign Test

  • Not Parametric
  • Difference
  • Level of Data : Nominal
  • Doesn't have independent groups
• Statistical Test : Chi-Squared Test

  • No Parametric
  • Difference/ Association
  • Level of Data : Nominal
  • Does have independent groups
• Statistical Test : Spearman's Rho

  • Not Parametric
  • Correlation
  • Level of Data : Ordinal
  • Doesn't have an independent group
• Statistical Test : Wilcoxon

  • Not Parametric
  • Correlation
  • Level of Data : Ordinal
  • Doesn't have an independent group
• Statistical Test : Mann-Whitney

  • Not Parametric
  • Difference
  • Level of Data : Ordinal
  • Does have independent groups
• Statistical Test : Pearson's r

  • Is parametric
  • Correlation
  • Level of Data : Interval/Ratio
  • Doesn't have independent groups
• Statistical Test : Unrelated T-Test

  • Is Parametric
  • Difference
  • Level of Data : Interval/Ratio
  • Does have independent groups
• Statistical Test : Related T-Test


  • Is Parametric
  • Difference
  • Level of Data : Interval/Ratio
  • Doesn't have independent groups
• What do inferential statistics allow us to do?

  Make inferences about populations from samples
• How do inferential statistics differ from descriptive statistics?

  Inferential statistics assess significance of relationships
• What does significance refer to in statistics?

  Findings due to a genuine relationship, not chance
• What do inferential tests use to determine results?

  Probability to ascertain likelihood of results
• What happens if the probability of results is below a certain level?

  We assume the results are significant
• What is the P value for a level of significance?

  P ≤ 0.10, P ≤ 0.05, P ≤ 0.01, P ≤ 0.001
• Why do hypotheses matter in inferential statistics?

  They determine acceptance or rejection of null hypothesis
• What happens if a test is significant?

  Reject the null hypothesis, accept alternative hypothesis
• What happens if a test is not significant?

  Accept the null hypothesis, reject alternative hypothesis
• What is a directional hypothesis also known as?

  One-tailed hypothesis
• Why is a directional hypothesis called one-tailed?

  Results are interested in one specific direction
• What is a non-directional hypothesis also known as?

  Two-tailed hypothesis
• Why is a non-directional hypothesis called two-tailed?

  It suggests a significant difference without direction
• What factors determine which inferential test to use?

  • Type of data
  • Type of research design
  • Test of difference or correlation
• What are the three types of experimental design?


  • Repeated measures
  • Independent groups
  • Matched pairs
• What are the four levels of measurement?

  • Nominal
  • Ordinal
  • Interval
  • Ratio
• Why is it important to know the level of measurement of the dependent variable?

  It influences the choice of statistical test
• What are the types of inferential tests?

  • Parametric: Pearson’s r, Unrelated t-test, Related t-test
  • Non-parametric: Sign test, Chi-squared test, Mann-Whitney, Wilcoxon, Spearman’s rho
• What characterizes parametric tests?

  They require interval or ratio data
• What characterizes non-parametric tests?

  They can be used with nominal or ordinal data
• What do nominal and ordinal data have in common?

  Both are classified as non-parametric data
• What do interval and ratio data have in common?

  Both are classified as parametric data
• What is required for a population to use parametric tests?

  The population must be normally distributed
• What is the significance of the bell curve in statistics?

  It represents normally distributed characteristics
• What can be checked for skewness in data?

  The distribution of scores (mean, median, mode)