The Importance of Variables in Research & Studies

What is the dependent variable (DV) in the research question: 'Does exercise improve mental health?'

• mental health

• exercise frequency

• diet

• sleep quality

Answer explanation

In the research question 'Does exercise improve mental health?', the dependent variable (DV) is what is being measured or affected. Here, 'mental health' is the outcome being evaluated in relation to exercise.

In the example provided, what are the independent and dependent variables when examining test scores of students who study at night vs. in the morning?

• Independent variable: time of study (night vs. morning)

• Dependent variable: test scores

• Independent variable: test scores

• Dependent variable: time of study (night vs. morning)

Answer explanation

The independent variable is the time of study (night vs. morning) because it is manipulated to observe its effect. The dependent variable is the test scores, as they are measured to see how they change based on the study time.

What is the independent variable in the example of causation related to exercising and weight loss?

• The independent variable is exercising.

• The independent variable is weight loss.

• The independent variable is diet.

• The independent variable is sleep.

Answer explanation

In the context of causation, the independent variable is the factor that is manipulated to observe its effect. Here, exercising is the independent variable that influences weight loss, making it the correct choice.

Exercising regularly is considered a causation for weight loss because:

• it increases metabolism and burns calories.

• it decreases metabolism and stores calories.

• it has no effect on metabolism or calories.

• it only builds muscle without affecting weight.

Answer explanation

Exercising regularly increases metabolism and burns calories, which contributes to weight loss. This is why the correct answer is that it increases metabolism and burns calories.

Which of the following is an example of a discrete variable?

• Height of students in a classroom

• Temperature

• Number of students in a class

• Weight of an individual

Answer explanation

A discrete variable is one that can take on a countable number of values. The 'number of students in a class' is discrete, as it can only be whole numbers. In contrast, height, temperature, and weight are continuous variables.

An independent variable is the variable that the researcher _______ to observe its effect.

• manipulates

• observes

• controls

• measures

Answer explanation

An independent variable is the one that the researcher manipulates to observe its effect on the dependent variable. This manipulation allows the researcher to determine causal relationships.

Fill in the blank: Continuous variables allow for _______ measurements and are often analyzed using statistical methods like mean, standard deviation, or regression.

• precise

• approximate

• random

• discrete

Answer explanation

Continuous variables allow for precise measurements, meaning they can take on any value within a range. This precision enables the use of statistical methods like mean and regression for analysis.

Which of the following is an example of a dependent variable?

• Type of diet in a weight-loss study

• Plant growth based on sunlight exposure

• Same soil type in a plant growth experiment

• People who drink more coffee perform better at work

Answer explanation

In the context of the question, 'Plant growth based on sunlight exposure' is a dependent variable because it changes in response to the independent variable, which is sunlight exposure. The other options do not represent dependent variables.

In a study showing that people who drink more coffee perform better at work, what is the confounding variable?

• The amount of sleep the participants get

• The type of coffee consumed

• The age of the participants

• The time of day the coffee is consumed

Answer explanation

The amount of sleep the participants get is a confounding variable because it can influence both coffee consumption and work performance, potentially skewing the results of the study.

What is a confounding variable?

• A variable that influences both the dependent variable and independent variable, causing a spurious association

• A variable that is always constant in an experiment

• A variable that only affects the independent variable

• A variable that only affects the dependent variable

Answer explanation

A confounding variable is one that affects both the dependent and independent variables, leading to a false association between them. This is why the correct choice is that it influences both, causing a spurious relationship.