Research Methods - Non Parametric Tests Flashcards
To learn the steps and criteria for Chi Squared, Mann Whitney U, Sign Test, Wilcoxon and Spearman
What is nominal data?
“name labels”
What is ordinal data?
“order values”
What is interval data?
No true 0, but equal intervals
Give two examples of nominal data:
- What is your gender? (Male/Female)
2. What colour is your hair? (Black/Brown/Blonde/Gray)
Give two examples of ordinal data:
- How do you feel today? (1=Very Un-happy 2=Unhappy 3=OK 4=Happy 5=Very Happy)
- How often do you eat breakfast? (0=Never 1=Rarely 2=Occasionally 3=Sometimes 4=Often etc.)
Give two examples of interval data:
- Celsius temperature
2. Ruler (cm)/(m)
What is independent measures design?
One group of ppts take part in one condition of an experiment
What is repeated measures design?
One group of ppts take part in both or all conditions of an experiment.
What is the criteria for Chi Squared?
Nominal data, IMD
What is the criteria for Mann Whitney U?
Ordinal data, IMD
What is the criteria for Wilcoxon?
Ordinal data, RMD
What is the criteria for Sign Test?
Nominal data, RMD
What is the criteria for Spear-man’s Rank?
2 sets of ordinal data, Correlation
Which tests involve ranking?
- Mann Whitney U
- Wilcoxon
- Spear-mans rank
How is the data ranked in Mann Whitney U?
You rank all the data from condition 1 and condition 2
How is the data ranked in Wilcoxon?
You rank the data of the differences between condition 1 and condition 2, ignoring 0 or minus signs
How is the data ranked in Spear-mans rank?
The data is ranked separately from variable 1 and variable 2
Which tests do not involve ranking?
- Chi Squared
2. Sign Test
In which tests does the observed value have to be larger than the critical value?
“first and last”
- Chi-squared
- Spear-man’s rank
Using Mann Whitney U, what is the next step after ranking the data?
You add up the (sum of the ranks) from condition 1 and condition 2
Using Mann Whitney U, what is the next step after you add up the sum of the ranks?
You use the smallest sum of (r1 or r2)
How do you find the calculated/observed value using Mann Whitney U?
Use the smallest sum of (r1 or r2) using the equation:
(n1+1)
U1 = n1n2 + ———– - E R1
2
(n2+1) U2 = n1n2 + ---------- - E R2
2
How do you find the critical value using Mann Whitney U?
You use the number of ppts
In Mann Whitney U, which value must be higher in order for it to be significant?
Critical value
What is the first step in Wilcoxon?
Find the difference for each ppt from condition 1 and condition 2
How do you find the calculated/observed value using Wilcoxon?
You add up the ranks of the least frequent sign (+/-)
How do you find the critical value using Wilcoxon?
Use the number of differences, ignoring 0
In Wilcoxon, which value must be higher in order for it to be significant?
Critical value
What is the first step of Chi Squared?
Work out the row total, column total and overall total
In Chi Squared, after you have worked out the overall total, what is the next step?
Work out the expected frequency for each cell
How do you work out the expected frequency in Chi Squared?
expected frequency = row total x column total
———————————-
overall total
In Chi Squared, after you have worked out the expected frequency, what is the next step?
You work out the observed value for each cell
How do you work out the observed value in Chi Squared?
Observed value = (observed - expected) 2
———————————-
expected
How do you find the calcluated/observed value in Chi Squared?
You add up the observed value for each cell to get the overall observed value
How do you find the critical value in Chi Squared?
You use degrees of freedom
What is the equation for degrees of freedom?
df = (number of rows-1) (number of columns-1)
In Chi Squared, which value must be higher in order for it to be significant?
The observed value
What is the first step in Sign test?
Establish whether you are using one-tailed or two-tailed hypothesis and add a column to show the flow of direction (-/+) and ignore no changes
How do you find the calculated/observed value in Sign test?
You add up the least frequent sign (+/-)
How do you find the critical value in Sign test?
You use the number of ppts
In Sign test, which value must be higher in order for it to be significant?
The critical value
After you have ranked data in Spear-man’s rank, what is the next step?
You find the differences between the ranks for each ppt
What is the third step in Spear-man’s rank?
You square the differences for each ppts
How do you find the calculated/observed value?
You add up the sum of the squared differences and use it in the equation:
6 x sum of d2 rho = 1 - ------------------
n2-n
How would you find the critical value using Spear-man’s rank?
Use the number of ppts
In Spear-man’s rank, which value must be higher in order for it to be significant?
The observed value
