Non-Parametric Tests (and parametric parts) Flashcards
When would you use a parametric test?
What’s the criteria?
(4 parts)
- You have normal distribution for your data
- Variances of data populations are equal
- Interval level of data
- No extreme scores (small range)
Non-parametric tests
What are the 5 tests?
- Mann-Whitney U Test
- Wilcoxon Signed Ranks Test
- Chi-square
- Binomial Sign Test
- Spearman’s Rho
Non-parametric Test
What 3 questions should you ask to help decide the test you need to do?
- What level of data do you have?- nominal or not
- Testing for a difference or correlation?- may say in question
- Experimental design?- Independent measures or repeated measures/ same or different participants
Non-parametric tests
What phrase can be used to remember the criteria?
- L= Level of data
- ION= Interval, Ordinal, Nominal
- D/C= Difference or correlation
- ED= Experimental Design
Mann Whitney U
What criteria is required for this test?
- Not nominal data
- Different participants- Independent measures
- Difference
Mann Whitney U
What are the steps to calculate?
- Rank scores from lowest to highest
- Use formula to find U
- Calculate the smaller U value
- (Given formula sheet)
Mann Whitney U
What is the level of significance?
- U value is less that critical value= reject null hypothesis as it’s significant
- U value is higher than critical value= accept null hypothesis as it’s insignificant
Wilcoxon Rank
What is the criteria for this test?
- Not nominal
- Repeated measures design (same participants)
- Difference
Wilcoxon
What are the steps to calculate?
- Calculate the difference between the values across the different conditions
- Rank differences
- Sum up the positive and negative ranks
- T is the smallest of the values
Wilcoxon
What is the level of significance?
- If W value is less than the CV= reject null hypothesis (it’s significant)
- If W value is more than the CV= accept null hypothesis (it’s not significant)
Chi-square
What is the criteria for this test?
- Nominal data
- Independent measures (different participants)
- Difference
Chi-square
What are the steps to calculate?
- Add totals for each column
- Calculate observed and expected frequencies (E= RxC/T) for each individual observed values
- Input each EV into formula then add values to get x2
- Find the df at 0.05 and check table of significance
5.
Chi-square
What is the level of significance?
- If calculated chi is less than CV= accept null hypothesis (insignificant)
- If calculated chi value is more than CV= reject null hypothesis (significant)
What is the criteria for this test?
(Binominal sign)
Nominal data
Difference
Same participants (repeated measures)
What are the steps to complete? (binominal sign?
- Calculate direction of difference between conditions (e.g. put a minus sign - after values in column 1 and keep consistent)
- Identify which sign is the least common (S+ S-)
- Look at CV table to obtain critical value for S
