statistical tests Flashcards
What are the two branches of statistical test?
parametric and non-parametric
What is the observed value?
the result from a statistical test
What is the critical value?
the number taken from a statistical table
What are the types of parametric test?
tests used in core studies e.g., t-tests
What are the types of non-parametric test?
- Binomial Sign
- Chi-Squared
- Wilcoxon Signed
- Mann Whitney U
- Spearman’s Rho
When are parametric tests used?
- Normal Distribution
- Interval/Ratio data
When are non-parametric tests used?
- Non-normal Distribution
- When the median (or mode) provides a better average
- Nominal, Ordinal, and Interval / Ratio data
What are the 3 factors than can be used to identify which statistical test should be used?
- difference or correlation
- experimental design (independent or repeated measures)
- Level of Data (Nominal, Ordinal, or Interval0
How do you know when to use a binomial Sign test?
- DV is nominal data
- Repeated Measures Design
How do you know if there is a significant difference by the result of the binomial test?
Observed value ≤ Critical value
What are the steps to the binomial tests?
1- assign a sign to conditions (+ or -)
2- ignore the same results across conditions
3- add up frequency of each sign
4- use least frequent sign (observed value)
5- n= total participants aside from those ignored
6- O ≤ C
How do you know when to use a Wilcoxon test?
- ordinal/interval data
- repeated measures design
How do you know there is a significant difference in a Wilcoxon test?
Observed Value ≤ Critical Value
What are the steps for a Wilcoxon test?
1- calculate difference (condition A - condition B)
2- rank (smallest to largest)
- ignore signs (for now)
- ignore any 0 value
3- use least frequent sign (positive or negative)
4- add up ranks of least frequent sign = observed value
5- compare to critical value
6- N= participants (do not use ignored)
7- O ≤ C
How do you know when to use a chi squared test?
- nominal data
- independent measures
How do you know there is significance in a chi squared test?
Observed value ≥ Critical value
What are the steps to a chi squared?
1- calculate row and column totals
2- calculate expected value for each condition
3- use formula for each condition
4- add up formula results for an observed value
5- compare to the degrees of freedom
What is the formula to find the expected value in a chi squared?
row total x column total / overall total
How do you find the observed value in a chi squared?
(observed-expected)²/ expected
What is the degrees of freedom equation in a chi squared?
(number of rows -1) x (number of columns -1)
How do you know when to use a spearman’s rho test?
if its a correlation
How can you tell if a relationship is significant when using a spearman’s rho test?
Observed value ≥ Critical value
What are the steps to a spearman’s rho test?
1- rank each variable (lowest to highest)
2- calculate difference between the ranks of the two variables (variable 1 - variable 2)
3- square the difference
4- total up all of the squared differences
5- use formula = observed value
6- compare observed value to critical value table
How do you know when to use a Mann Whitney U test?
- independent measures
- interval data
What are the steps to a Mann Whitney U?
- rank all participant results (lowest - highest)
- put the ranks of participants into the og table
- add up all the ranks for each condition
- use the smallest total
- formula
- O ≤ C
