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Chapter 3: Problem 1

How sensitive to changes in water temperature are coral reefs? To find out, measure the growth of corals in aquariums where the water temperature is controlled at different levels. Growth is measured by weighing the coral before and after the experiment. What are the explanatory and response variables? Are they categorical or quantitative?

Short Answer

Expert verified
Explanatory variable: water temperature (quantitative); Response variable: coral growth (quantitative).

Step by step solution

01

Identify the Variables

To solve this exercise, we first need to identify the variables involved. The explanatory variable is the water temperature level in the aquariums, as this is what is manipulated to observe its effect. The response variable is the growth of the corals, which is what is measured after the experiment.
02

Classify the Explanatory Variable

The explanatory variable is water temperature. Water temperature is quantitative because it can be represented with numerical values corresponding to different degrees of temperature.
03

Classify the Response Variable

The response variable is coral growth, measured by the change in weight. This is also quantitative because it involves measuring the change in weight, which is expressed in numerical terms.

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Key Concepts

These are the key concepts you need to understand to accurately answer the question.

Explanatory Variable
In research, the explanatory variable is the one you manipulate to observe its effect on another variable. It is the cause in a cause-and-effect relationship. In our coral reef study, the water temperature is the explanatory variable.
This means that we adjust the water temperature in different tanks to see how it influences coral growth.
  • We control this variable by setting it at various specific levels.
  • It is the factor that we change on purpose to test the impact it has.
Understanding the explanatory variable helps us establish a framework for analyzing the results. By carefully monitoring changes we make to this variable, we gain insights into how sensitive coral reefs are to temperature variations.
Response Variable
The response variable is what you measure in an experiment and is affected by changes in the explanatory variable. In the case of our coral reef experiment, coral growth is the response variable. This is what we are actually interested in understanding.
  • We measure growth by weighing the coral before and after changing the water temperature.
  • Assessing the response variable helps researchers to see if the changes in the explanatory variable have made any difference.
This variable provides direct evidence of the experiment's impact. It helps us to answer the fundamental question of how coral growth is affected by different water temperatures.
Quantitative Variable
A quantitative variable is one that can be measured numerically. In this experiment, both water temperature and coral growth are quantitative.
Water temperature is a quantitative variable because it can be expressed in numerical values such as 25掳C, 28掳C, etc. This allows for precise adjustments and comparisons.
  • Temperature can be increased or decreased in fixed amounts to see different effects.
  • Numerical data like this helps to provide clear, measurable outcomes in research.
Similarly, coral growth is quantitative because it is measured using weight. This measurable aspect provides a clear way to track changes and make data comparisons.
  • Weight change is easy to document and analyze.
  • Using such numerical data provides concrete insights into coral development patterns.
Quantitative variables are central in experiments because they offer clear and objective data that can be easily analyzed to draw meaningful conclusions.

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Most popular questions from this chapter

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