In a study, the effect of stress on sleep quality varies by level of mindfulness. Mindfulness functions as a

In a study, the effect of stress on sleep quality varies by level of mindfulness. Mindfulness functions as a

• A. Moderator.
• B. Mediator.
• C. Confounder.
• D. Outcome.

Answer: (A)

The main idea here is moderation: a variable that changes how strong the relationship is between two other variables. When the effect of stress on sleep quality depends on how mindful someone is, mindfulness is acting as a moderator. This shows up as an interaction: the slope of stress predicting sleep quality differs across levels of mindfulness (for example, high mindfulness might buffer the negative impact of stress on sleep, while low mindfulness could amplify it). If mindfulness were a mediator, stress would influence mindfulness, which would then influence sleep quality—a causal chain rather than an alternate effect size depending on mindfulness. A confounder would be related to both stress and sleep quality in a way that could distort the observed relationship, not change its strength across levels of mindfulness.

The main idea here is moderation: a variable that changes how strong the relationship is between two other variables. When the effect of stress on sleep quality depends on how mindful someone is, mindfulness is acting as a moderator. This shows up as an interaction: the slope of stress predicting sleep quality differs across levels of mindfulness (for example, high mindfulness might buffer the negative impact of stress on sleep, while low mindfulness could amplify it).

If mindfulness were a mediator, stress would influence mindfulness, which would then influence sleep quality—a causal chain rather than an alternate effect size depending on mindfulness. A confounder would be related to both stress and sleep quality in a way that could distort the observed relationship, not change its strength across levels of mindfulness.