In a study examining the relationship between hours of sleep and reaction time, researchers recorded the number of hours participants slept the night before a test and their reaction times during the test. Which of the following correctly identifies the predictor variable and the response variable in this study? a. Predictor variable: Reaction time, Response variable: Hours of sleep b. Predictor variable: Hours of sleep, Response variable: Reaction time c. Predictor variable: Hours of sleep, Response variable: Number of participants d. Predictor variable: Reaction time, Response variable: Number of hours of sleep

**Step 1: Identify the variables in the study** The study examines the relationship between: - **Hours of sleep** (recorded from the night before the test) - **Reaction time** (measured during the test) **Step 2: Define predictor and response variables** - The **predictor variable** (also called the independent variable) is the one that is manipulated or categorized to observe its effect. - The **response variable** (also called the dependent variable) is the one that is measured or expected to change in response to the predictor. **Step 3: Assign the variables** In this study: - The predictor variable is the number of \( \text{hours of sleep} \) because it is assumed to influence the reaction time. - The response variable is the \( \text{reaction time} \) during the test because it depends on how much sleep the participant had. **Step 4: Match with the provided choices** Given the definitions: - Option a: Predictor variable: Reaction time, Response variable: Hours of sleep - Option b: Predictor variable: Hours of sleep, Response variable: Reaction time - Option c: Predictor variable: Hours of sleep, Response variable: Number of participants - Option d: Predictor variable: Reaction time, Response variable: Number of hours of sleep The correct choice is: \( \textbf{b. Predictor variable: Hours of sleep, Response variable: Reaction time} \)