Parametic Assumptions and Stats Decision Tree

Question 1

What are the 4 parametric assumptions

Answer 1

1. Interval data
   - Outcome variable should be interval or ratio level data
   - If data is categorical you have to use non-paramedic test
2. Normal distribution
3. Homogeneity of variance
   - Are the variances of our sample approximately equal
   - Approx. equal = no more than 3x larger
4. No extreme scores

Question 2

What are the 7 tests

Answer 2

• Pearson’s r
• Spearman’s rho
• Chi square
• Related t test
• Wilcoxon
• Independent t test
• Mann-Whitney

Question 3

When do you use Pearson’s r

Answer 3

1. Relationships
2. Continuous variable
3. Parametic data

Question 4

When do you use Spearman’s rho

Answer 4

1. Relationships
2. Continuous variable
3. Non-Parametric data

Question 5

When do you use chi square

Answer 5

1. Relationships

2. Categorical data

Question 6

When do you use related t test

Answer 6

1. Differences
2. Within participants
3. Parametric data

Question 7

When do you use Wilcoxon

Answer 7

1. Differences
2. Within participants
3. Non-parametric data

Question 8

When do you use independent t test

Answer 8

1. Differences
2. Between participants
3. Parametric data

Question 9

When do you use Mann-Whitney

Answer 9

1. Differences
2. Between participants
3. Non-Paramedic data

Question 10

Parametric or non-parametric

Answer 10

• If 3+ of assumptions can be met then use parametric tests

- If 2 or less of assumptions can be met then use non-parametric tests