## Multiple choice questions

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

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

#### Answer: Repeated-measures analysis of variance

When the assumption of sphericity is violated, what action is needed?

1. Correct the model degrees of freedom and correct the error degrees of freedom.
2. Correct the model degrees of freedom.
3. Correct the error degrees of freedom.
4. Correct the F-ratio.

#### Answer: Correct the model degrees of freedom and correct the error degrees of freedom

Which of the following statements about the assumption of sphericity is not true?

1. It is the assumption that the variances for levels of a repeated-measures variable are equal.
2. It is tested using Mauchly’s test in SPSS.
3. It is automatically met when a variable has only two levels.
4. It is not assumed by multivariate tests.

#### Answer: It is the assumption that the variances for levels of a repeated-measures variable are equal

A nutritionist conducted an experiment on memory for dreams. She wanted to test whether it really was true that eating cheese before going to bed made you have bad dreams. Over three nights, the nutritionist fed people different foods before bed. On one night they had nothing to eat, a second night they had a big plate of cheese, and the third night they had another dairy product, milk, before bed. All people were given all foods at some point over the three nights. The nutritionist measured heart rate during dreams as an index of distress. How should these data be analysed?

1. One-way independent ANOVA
2. One-way repeated-measures ANOVA
3. Three-way repeated-measures ANOVA
4. Three-way independent ANOVA