Use this worksheet to practice identifying the independent and dependent variables in various experimental scenarios.

Problem: Identify the independent and dependent variables in the given descriptions of experiments.

#### Explanation of Independent and Dependent Variables:
- Independent Variable (IV): The variable that is manipulated or changed by the experimenter. It is the cause.
- Dependent Variable (DV): The variable that is measured or observed to see how it responds to changes in the independent variable. It is the effect.

Now, let's analyze each scenario step by step:

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1. Students watched a cartoon either alone or with others and then rated how funny they found the cartoon to be.

- Independent Variable (IV): Whether students watched the cartoon alone or with others. This is the factor being manipulated.
- Dependent Variable (DV): How funny the students rated the cartoon. This is the outcome being measured.

Answer:
- Independent Variable: Watching the cartoon alone or with others.
- Dependent Variable: Ratings of how funny the cartoon was.

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2. Taking a nap in the afternoon makes people more relaxed and less irritable for the rest of the day.

- Independent Variable (IV): Taking a nap in the afternoon. This is the factor being manipulated.
- Dependent Variable (DV): Levels of relaxation and irritability for the rest of the day. These are the outcomes being measured.

Answer:
- Independent Variable: Taking a nap in the afternoon.
- Dependent Variable: Levels of relaxation and irritability.

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3. If leaf color change is related to temperature, then exposing plants to low temperatures will result in changes in leaf color.

- Independent Variable (IV): Temperature (specifically, exposure to low temperatures). This is the factor being manipulated.
- Dependent Variable (DV): Changes in leaf color. This is the outcome being measured.

Answer:
- Independent Variable: Temperature (low temperatures).
- Dependent Variable: Leaf color.

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4. Eating breakfast in the morning increases the ability to learn in school.

- Independent Variable (IV): Eating breakfast in the morning. This is the factor being manipulated.
- Dependent Variable (DV): Ability to learn in school. This is the outcome being measured.

Answer:
- Independent Variable: Eating breakfast in the morning.
- Dependent Variable: Ability to learn in school.

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5. If skin cancer is related to ultraviolet light, then people with a high exposure to UV light will have a higher frequency of skin cancer.

- Independent Variable (IV): Exposure to ultraviolet (UV) light. This is the factor being manipulated or observed.
- Dependent Variable (DV): Frequency of skin cancer. This is the outcome being measured.

Answer:
- Independent Variable: Exposure to UV light.
- Dependent Variable: Frequency of skin cancer.

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Final Answers:

1.
- Independent Variable: Watching the cartoon alone or with others.
- Dependent Variable: Ratings of how funny the cartoon was.

2.
- Independent Variable: Taking a nap in the afternoon.
- Dependent Variable: Levels of relaxation and irritability.

3.
- Independent Variable: Temperature (low temperatures).
- Dependent Variable: Leaf color.

4.
- Independent Variable: Eating breakfast in the morning.
- Dependent Variable: Ability to learn in school.

5.
- Independent Variable: Exposure to UV light.
- Dependent Variable: Frequency of skin cancer.

Boxed Final Answer:
\[
\boxed{
\begin{array}{ll}
1. & \text{IV: Watching the cartoon alone or with others} \\
& \text{DV: Ratings of how funny the cartoon was} \\
2. & \text{IV: Taking a nap in the afternoon} \\
& \text{DV: Levels of relaxation and irritability} \\
3. & \text{IV: Temperature (low temperatures)} \\
& \text{DV: Leaf color} \\
4. & \text{IV: Eating breakfast in the morning} \\
& \text{DV: Ability to learn in school} \\
5. & \text{IV: Exposure to UV light} \\
& \text{DV: Frequency of skin cancer} \\
\end{array}
}
\]