14. Nonparametric Tests 1

Question 1

When are nonparametric tests used?

Answer 1

when assumptions of a parametric test has been violated

Question 2

How do nonparametric tests work?

Answer 2

by ranking data

• lowest score ranked 1
• next highest score ranked 2
• etc..

Question 3

Nonparametric tests are powerful as long as

Answer 3

the assumptions of a parametric test have been violated

Question 4

What measure of central tendency do nonparametric tests use?

Answer 4

median (as opposed to mean in parametric)

Question 5

What type of graph do you generate before running nonparametric tests?

Answer 5

box and whisker

Question 6

What types of things can you compare for nonparametric tests?

Answer 6

• 2 independent groups
• 2 related groups
• 3+ independent groups
• 3+ related groups

Question 7

compare 2 independent groups

Answer 7

Mann-Whitney U test

Question 8

compare 2 related scores/samples

Answer 8

Wilcoxin rank-sum (W) test

Question 9

compare 3+ independent groups

Answer 9

Kruskall-Wallis ANOVA by ranks

Question 10

compare 3+ related groups

Answer 10

Friedman 2 way ANOVA by ranks

Question 11

Mann Whitney test (U) is the equivalent to

Answer 11

independent/unpaired t-test

Question 12

How do nonparametric tests work?

Answer 12

use the values of the ranks to assess differences between groups

Question 13

Which two tests can be used for comparing two independent groups?

Answer 13

Mann-Whitney (U)

Wilcoxin rank-sum (W)

Question 14

Wilcoxin rank-sum (W) is the equivalent of

Answer 14

dependent/paired t-test

Question 15

The Kruskall-Wallis test is the equivalent to

Answer 15

1-way ANOVA

Question 16

What is the statistic used for the Kruskall-Wallis test (or rather, the nonparametric ANOVA)

Answer 16

chi square statistic

Question 17

Why a chi square stat?

Answer 17

the data creates a chi square distribution (special distribution type)

Question 18

When must post-hoc tests be performed for a Kruskall-Wallis test?

Answer 18

if H stat is less than .05

Question 19

What post hoc test would be performed if H-stat is less than .05?

Answer 19

Mann-Whitney test for each comparison with a Bonferroni-corrected alpha

*carefully choose to avoid Type II error

Question 20

The Friedman’s 2-way ANOVA is the equivalent of this test

Answer 20

repeated measures anova

Question 21

What test statistic is used for the Friedman’s test?

Answer 21

chi-square

Question 22

When must you perform post-hoc test for Friedman’s?

Answer 22

x^2 stat is less than .05