Dissolved oxygen (DO) is an important indicator of water quality, and oxygen levels that are too high or too low can harm aquatic ecosystems. A biologist noticed that fish were dying in a local lake and was concerned that the DO levels were too low to support aquatic life due to extremely high temperatures that summer. To measure the DO levels, she brought back several lake water samples to her laboratory to measure the DO concentration as a function of temperature. To do this, she heated several samples of lake water to various temperatures and then measured the DO concentration in each sample. Some samples were kept at the outdoors temperature.
Which is the dependent variable?

Question

Quizplus · Accepted Answer

The dependent variable is the variable whose change is being manipulated as the independent variable is changed. Thus, the dependent variable is dependent on changes in the independent variable. In this case, the temperature is modified to determine how it influences the DO concentration. Since the DO concentration is what is actually being measured, it is the dependent variable.

Dissolved Oxygen (DO) Is an Important Indicator of Water Quality