Discovering Statistics Using IBM SPSS Statistics

A researcher was interested in stress levels of lecturers during lectures. She took the same group of 8 lecturers and measured their anxiety (out of 15) during a normal lecture and again in a lecture in which she had paid students to be disruptive and misbehave. The data were not normally distributed. Which test should she use to compare her experimental conditions? 

Answer choices

1. Paired samples t-test
2. Mann–Whitney test
3. Wilcoxon rank-sum test
4. Wilcoxon signed-rank test

A researcher measured the same group of people’s physiological reactions while watching horror films and compared them to when watching erotic films. The resulting data were skewed. What test should be used to analyse the data? 

Answer choices

1. Independent t-test
2. Wilcoxon signed-rank test
3. Dependent (related) t-test
4. Mann–Whitney test

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

Answer choices

1. Independent analysis of variance
2. Repeated-measures analysis of variance
3. Friedman’s ANOVA
4. Kruskal–Wallis test

Assuming the assumptions of parametric tests are met, non-parametric tests, compared to their parametric counterparts: 

Answer choices

1. Are all of these.
2. Are more conservative.
3. Are less likely to accept the alternative hypothesis.
4. Have less statistical power.

What symbol represents the test statistic for the Mann–Whitney test?

Answer choices

1. Ws
2. T
3. U
4. H