# Discovering Statistics Using IBM SPSS Statistics

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## Chapter Specific Resources

## Multiple choice questions

**The combined effect of two variables on another is known conceptually as _______, and in statistical terms as _________ **

__Answer choices__

- Mediation, an interaction effect
- Moderation, a direct effect
- Moderation, an interaction effect
- Mediation, a direct effect

#### Answer: Moderation, an interaction effect

**Imagine we wanted to look at the relationship between the number of hours spent practising the guitar per week and skill level. If we had reason to believe that the strength or direction of the relationship between these variables will be affected by level of enjoyment, what type of analysis should we conduct on these data?**

__Answer choices__

- Moderation analysis
- Mediation analysis
- Two-way repeated-measures ANOVA
- ANCOVA

#### Answer: Moderation analysis

**Taking mean centring for a given variable is achieved by:**

__Answer choices__

- Taking the mean of all scores (ignoring from which variable they come) and subtracting each score from it.
- Taking each score and subtracting from it the mean of all scores (for that variable).
- Taking each score and dividing it by the mean of all scores (for that variable).
- Taking each score, subtracting the mean and then dividing by the standard deviation.

#### Answer: Taking each score and subtracting from it the mean of all scores (for that variable)

**Why is it a good idea to centre your variables when conducting a moderation analysis?**

__Answer choices__

- It makes the data normally distributed.
- It aids the interpretation of the indirect effect.
- Because it reduces multicollinearity between main effects and the interaction effect.
- It ensures the relationship between the predictor and outcome is linear.

#### Answer: Because it reduces multicollinearity between main effects and the interaction effect

**Imagine we wanted to look at whether enjoyment of guitar playing influences the relationship between time spent practising and skill level. How would we know if we had a significant moderation effect?**

__Answer choices__

- If the interaction of time spent practising and skill level was a significant predictor of enjoyment.
- If the relationship between time spent practising and skill level does not change when enjoyment is entered into the model.
- If the relationship between time spent practising and skill level disappears when enjoyment is entered into the model.
- If the interaction of time spent practising and enjoyment was a significant predictor of skill level.

#### Answer: If the interaction of time spent practising and enjoyment was a significant predictor of skill level.