# Non-Parametric Tests Flashcards Preview

## PS3021 Stats > Non-Parametric Tests > Flashcards

Flashcards in Non-Parametric Tests Deck (19)
1
Q

What do parametric tests aim to do?

A

Estimate sample means and variances and ask how likely it is the parameters are the same.

2
Q

What do non-parametric tests aim to do?

A

Find out how likely it is that the data come from one distribution.

3
Q

What do you use a non-parametric test?

A

When data is ordinal and a non-parametric test exists.

4
Q

What kind of set of methods are non-parametric tests?

A

Eclectic.

5
Q

What kind of set of methods are parametric tests?

A

They use one framework: GLM.

6
Q

What descriptive statistics are most appropriate with ordinal data?

A

A five number summary.

7
Q

What does a sign test ask?

A

Is the sample median the same as a hypothesised value?

8
Q

What are more powerful sign tests more likely to detect?

A

Differences that reflect true differences between populations.

9
Q

What is Wilcoxon’s solution to finding probabilities with moderately sized samples?

A

Converting to a z-score.

10
Q

What is different about a median in ordinal compared to scale data?

A

A, say, 2 unit difference below the median may not be the same as a 2 unit difference above the median.

11
Q

What does scholastic ordering allow us to investigate?

A

Whether the data values in one group are likely to be smaller than the data values in a second group.

12
Q

What do signed and Wilcoxin tests assume about samples?

A

That they are dependent.

13
Q

What does the Mann-Whitney U assume about samples?

A

That they are independent.

14
Q

When is it most important to use exact probabilities in the Mann-Whitney U?

A

When sample sizes are different.

15
Q

What is the implication of Kolmogorov-Smirnov being sensitive to changes in means?

A

One distribution is shifted compared to the other, creating a large gap.

16
Q

What is the implication of Kolmogorov-Smirnov being sensitive to changes in variance/range?

A

One distribution rises faster than the other, creating a large gap.

17
Q

Which non-parametric test is functionally equivalent to 1-way between subjects ANOVA?

A

Kruskal-Wallis.

18
Q

Which non-parametric test is functionally equivalent to 1-way within subjects ANOVA?

A

Friedman.

19
Q

What is the main assumption of the Kruskal-Wallis?

A

That all distributions have the same shape.