Question

In research on whether sugar causes hyperactivity, researchers randomly assign children to receive no sugar. small amounts of sugar, or large amounts of sugar. They then observe and code activity levels. In this case, the sugar level is the a. outcome variable. b. dependent variable. c. independent variable. d. control condition.

Short answer

The sugar level is the independent variable.

Step-by-step solution

Understanding the Variables

In experimental research, it's essential to understand the roles of different variables. The outcome or result of the experiment is called the dependent variable, while the variable that is manipulated to observe its effect is called the independent variable. In this case, sugar levels are manipulated, and activity levels are measured as a result.

Identifying the Dependent Variable

The dependent variable is what the researchers measure to see if there is an effect of the independent variable. In this experiment, the dependent variable is the children's activity level, as it is what the researchers are observing and coding based on the sugar intake.

Identifying the Independent Variable

The independent variable is the factor that is changed or controlled in the experiment. Here, the researchers randomly assign different levels of sugar intake (no sugar, small amounts of sugar, or large amounts of sugar) to the children, making the sugar level the independent variable.

Recognizing the Control Condition

The control condition serves as a baseline for comparison in an experiment. In this study, the control condition could be the group of children who receive no sugar, as this group would provide a comparison to those who consume sugar.

Determining the Correct Answer

With sugar level as the manipulated variable, it is the independent variable. Therefore, among the given options, the correct choice is c. independent variable.

Key concepts

Independent Variable

In experimental research, an independent variable is a fundamental concept that represents the factor researchers manipulate to observe its impact on another variable. For example, in a study examining whether sugar causes hyperactivity in children, researchers may vary sugar intake levels among participants. This manipulation occurs in three groups with different sugar consumption: no sugar, small amounts of sugar, and large amounts of sugar.

The independent variable is crucial as it sets the stage for observing changes and measuring outcomes. In our example, sugar levels represent the independent variable. By methodically altering sugar levels, researchers can pinpoint the precise effects, if any, sugar has on the dependent variable, which is the children's activity levels in this experiment.

To summarize:

• It is the manipulated factor in an experiment.
• Researchers control it to examine its effects on another variable.
• Different treatments or levels are given across experimental groups.

Dependent Variable

The dependent variable stands in direct contrast to the independent variable. It represents the measured outcome that researchers aim to explain or predict based on changes in the independent variable. Continuing with our example of sugar and hyperactivity, the dependent variable is the children's activity levels.

Researchers observe and code these activity levels to understand the potential effects of different sugar consumption levels. Any variation in the activity levels after altering the sugar intake provides valuable insight into how the independent variable affects this outcome.

To make sense of dependent variables, consider these aspects:

• It's what the experiment seeks to explain.
• Observations are recorded to see the impact of manipulating the independent variable.
• The outcome or response to experimental conditions.

Control Condition

The control condition is a critical element in experimental designs, acting as a benchmark or baseline. It helps researchers make accurate comparisons by mitigating the potential influence of external variables. In the context of our sugar intake experiment, the control condition could be represented by the group of children who are not given any sugar.

This group serves as an essential comparison point, highlighting any differences in activity levels that emerge in sugar-consuming groups. Ideally, changes or lack thereof in this group help validate findings across the experiment by ensuring observed effects are due primarily to the manipulated independent variable, not other extraneous variables.

Key points about control conditions:

• Serves as a comparison group in an experiment.
• Does not receive the treatment or factor under investigation.
• Helps isolate the effect of the independent variable.