Chapter 6- Non-parametric models

1.

1 point

A researcher measured people's physiological reactions to horror films. He split the data into two groups: males and females. The resulting data were significantly skewed and men and women had equal variances. What test should be used to analyse the data?

Wilcoxon signed-rank test

Mann–Whitney test

Paired-samples t-test

Independent t-test

2.

1 point

A researcher measured people's physiological reactions while watching horror films and compared them to when watching erotic films, and a documentary about wildlife. Different people viewed each type of film. The resulting data were skewed. What test should be used to analyse the data?

Friedman's ANOVA

Repeated-measures analysis of variance

Independent analysis of variance

Kruskal–Wallis test

3.

1 point

Non-parametric tests are used when:

All of these.

The assumptions of parametric tests have not been met.

You want to increase the power of your experiment.

You have more than the maximum number of tied scores in your data set.

4.

1 point

What is the non-parametric equivalent of the independent t-test?

Spearman's rho

Wilcoxon signed-rank test

Friedman's ANOVA

Mann–Whitney U test

5.

1 point

What is the parametric equivalent of the Wilcoxon signed-rank test?

The independent t-test

Pearson's r correlation

Independent ANOVA

The paired samples t-test

6.

1 point

Which of the following non-parametric tests does not rely on the calculation of ranks?

Wilcoxon rank-sum test

Wilcoxon signed-rank test

They all rely on the calculation of ranks.

Kruskal–Wallis test

7.

1 point

The _______ and _______ tests are calculated by ranking all of the scores from the two independent conditions that you are comparing from lowest to highest and adding up the ranks separately for each condition. The lowest of these summed ranks is the test statistic.

Wilcoxon signed-rank, Mann–Whitney U

Mann–Whitney U, Wilcoxon rank-sum

Wilcoxon signed-rank, Jonckheere–Terpstra

Friedman's ANOVA, Wilcoxon signed-rank

8.

1 point

The _______ test is based on calculating the difference between two sets of scores, making a note of the sign of the difference (positive or negative) and then ranking the differences from lowest to highest ignoring whether they are positive or negative.

Wilcoxon rank-sum test

Dependent t

Wilcoxon signed-rank test

Mann–Whitney U test

9.

1 point

What is the Kruskal–Wallis test based upon?

Residuals

Ranks

Intervals

Means

10.

1 point

What symbol represents the test statistic for the Wilcoxon signed-rank test?

H

Ws

U

T

11.

1 point

What symbol represents the test statistic for the Kruskal–Wallis test?

T

Ws

H

U

12.

1 point

Which of the following tests would you use to assess whether there is a significant difference between the mean ranks of two independent conditions?

Wilcoxon rank-sum test

Friedman's test

Kruskal–Wallis test

Spearman's rho

13.

1 point

You have carried out a Kruskal–Wallis test. There are significant differences between the three groups you are testing. How might you conduct your pairwise comparisons?

Perform t-tests

Perform Wilcoxon rank-sum tests

None of these. Post hoc analyses cannot be carried out using non-parametric tests.

Perform Mann–Whitney tests

14.

1 point

What is the problem with doing multiple pairwise comparisons to follow-up a significant Kruskal–Wallis test?

It inflates the familywise error rate.

It potentially masks important differences between variables.

It decreases the significance of the Kruskal–Wallis test

None of these.

15.

1 point

What can be done to reduce the inflated familywise error rate that occurs when performing multiple pairwise comparisons to follow up a significant Kruskal–Wallis test?

Use a higher probability as our threshold for significance.

Use the Jonckheere–Terpstra test.

Use a lower probability as the threshold for significance.

None of these are correct.

16.

1 point

What is the Jonckheere–Terpstra test used for?

To control for the familywise error rate.

To test for an ordered pattern to the medians of the groups you're comparing.

To test for an ordered pattern to the means of the groups you're comparing.

To test whether the variances in your data set are approximately equal.

17.

1 point

When the groups have unequal numbers of participants in them then the test statistic (Ws) for the Wilcoxon rank-sum test is:

The sum of the ranks for the two groups

The value of the smaller summed rank

The largest rank subtracted by the smallest rank

The sum of ranks in the group that contains the fewer people

18.

1 point

When the groups have equal numbers of participants in them then the test statistic (Ws) for the Wilcoxon rank-sum test is:

The largest rank subtracted by the smallest rank

The smallest rank subtracted by the largest rank

The summed value of the ranks for the two groups

The value of the smaller summed rank