Choosing a statistical test

• What are the three levels of measurement?

  Nominal, ordinal and interval
• What is nominal data?

  Named distinct categories e.g. sex, eye colour
• What is ordinal data?

  Data that is ordered in some way, but the actual value of the figure isn't measurable (doesn't have a unit) e.g. least to most aggressive
• What is interval data?

  Measured along a scale (has units) where the distance between one value and the next is equal and standardised e.g. temperature in Celsius
• What are the three factors used to decide which statistical test to use?

  1. Difference (test of difference or correlation)

  2. Design (independent groups or repeated measures)

  3. Data (nominal, ordinal or interval)
• Which two experimental designs are known as related?

  Repeated measures and matched pairs design
• Which experimental design is unrelated?

  Independent groups
• What is the criteria for using a parametric test?

  1. Interval data

  2. Population is normally distributed

  3. Variance between two samples is not statistically significant
• Choosing a statistical test table