Comparison Of Outcome Variables

Question 1

Parametric tests are used when:

Answer 1

1. There is independence between variables
2. Values take on a normal distribution
3. Homogenous variances e.g. equal variances between individual grps

Question 2

Parametric T-test is used when..

Answer 2

There are 2 groups.

The 3 types:
1. 1 sample t-test: comparing the average of one group against the established, set average
2. 2 sample t-test: comparing the averages of 2 separate groups
3. Paired T-test: 2 groups measured at 2 separate instances

Question 3

Parametric ANOVA is used when..

Answer 3

There are more than 2 groups to be tested

Question 4

Non-parametric tests are used when..

Answer 4

1. Data is ordinal (has a scale)
2. Asymmetric distribution (e.g. presence of outliers)
3. Heterogenous variances (e.g. values have wonky intervals)

Question 5

What are the non-parametric T-test equivalents?1

Answer 5

1. Single-sample Wilcoxon test (1-sample t-test)
2. Mann Whitney U test/Wilcoxon’s rank sum test (2-sample t-test)
3. Wilcoxon’s signed rank test (paired t-test)
4. Kruskal-Wallis analysis of variance, >2grps (ANOVA)

Question 6

Hypothesis testing. What is your null and alternative hypothesis?

Answer 6

Null hypothesis, Ho: there is no difference between the groups
Alternative hypothesis, H1: there is a difference between groups

Question 7

What does the P-value tell u in hypothesis testing?

Answer 7

P-value: the probability of the occurrence of a given event
- p-value>0.05: accept null hypothesis, there is no difference between the groups
- p-value<0.05: reject null hypothesis, there is a difference between groups

Question 8

One sample kolmogorov smirnov test is a..

Answer 8

One sample t test

Question 9

Wilcoxon rank sum test is a

Answer 9

Two sample t test
(X=Y)

Question 10

Mann whitney test is a

Answer 10

Two sample t-test (X>Y)

Question 11

Wilcoxon signed rank test is a

Answer 11

Paired t test

Question 12

Non parametric equivalent of 1 sample t test is..

Answer 12

1 sample wilcoxon signed rank test

Question 13

Non-parametric equivalent of 2-sample unpaired t-test is..

Answer 13

Wilcoxon test

Question 14

Non-parametric equivalent of 2-sample paired t-test is..

Answer 14

Mann whitney

Question 15

Non-parametric equivalent of 1 way ANOVA is..

Answer 15

Kruskal-willis test

Question 16

Non parametric equivalent of pearson’s correlation is..

Answer 16

Spearman’s correlation