Exam 11: Moderation, Mediation and Multicategory Predictors

A researcher was interested in the combined influence of physical activity (measured in minutes per day) and body image (measured on a scale of negative to positive) on levels of self-esteem (measured on a scale of negative to positive) in adolescent girls. What sort of analysis would be his best choice?

What is a moderator variable?

How would you interpret the following Sobel Test results: b = 0.134, z = 1.29, p = 0.510?

A health researcher had conducted trials testing the influence of age and cancer survival rates. She found a significant relationship between the two variables, with younger patients more likely to survive for two years following the completion of treatment than older patients. However, during the clinical trials she observed that a significant number of her older participants had good survival rates, irrespective of their ages and she suspected that their positive mental attitudes might also have an influence on their likelihood of survival. What sort of analysis should she conduct to explore this further?

In the researcher's analysis of what influences self-esteem in adolescent girls he found that the interaction of time spent in daily physical activity and body image level was a significant predictor of self-esteem. What sort of analysis does he need to do to work out the nature of the moderation effect?

A doctor conducted research into the influence of consumption of coffee (measured in cups consumed) and social media (measured in minutes daily spent on social media) on students' academic performance (measured by an end of term test score). She reported the following: Coffee (centred), b = 0.190, t = 3.23, p = 0.015. How would you interpret her findings?

Why is it better to use confidence intervals to identify indirect effects rather than the Sobel test?

What would you have to create in order to include categorical predictors in a moderation or mediation analysis?

A sports scientist conducted an analysis of the relationship between consumption of energy drinks (measured in units consumed daily) and athlete performance in a physical test (measured by test score). He had found that there was a positive relationship between the predictor and the outcome variable. However when he introduced the variable consumption of protein (measured in daily calories obtained from protein) he found that the strength of the original relationship weakened. How might he now summarise the relationship between energy drinks and physical performance?

A doctor conducted further clinical trials on the new drug's relationship to patient wound healing times; building on her previous study, she was interested in the potential mediating effects of patient age. She conducted a mediation analysis and had the following output: b = 0.31, 95% CI [0.01, 0.30], p = 0.054. How would you interpret her results?

A doctor conducted clinical trials on a new drug's relationship to patient wound healing times and had the following result: b = 0.46, p = 0.02. How would you interpret her results?

What are two of the advantages of using the PROCESS tool instead of the usual regression menu in SPSS?

In the doctor's research on coffee consumption, social media usage and students' academic performance (Coffee (centred), b = 0.190, t = 3.23, p = 0.015), which is the mediator variable?

Why is centring variables important in moderation analysis?

What does a significant result in a Sobel test mean?

What is the interaction effect?