Question

The Zoo is designing a new Hippo River exhibit. They're interested in the possibility of using wetlands areas to provide natural biological filtration (conversion of nitrogenous waste into nitrate and the removeal of nitrate from the system). In this system wetlands grasses would use nitrate from the river water as food, effectively removing it from the river. Research ?: Does sweetgrass or sedge (two wetlands grasses) achieve a lower concentration of nitrate in the river water?

Classify each of the following variables as the dependent, independent, or confounding variables described in this proposed research question?

type of grass:

the mass of nitrate removed from the river:

amount of grass eaten by hippos:

the season:

the concentration of the nitrate in the river:

Answer 1

A dependent variable is the one on which the impact of independent variable is to be observed. This implies that dependent variable changes and independent variable remains constant.

A co-founding variable is an outside influence that spuriously associate with both the dependent and independent variable and change their effect in any given experiment.

On the explanation provided above, the classification of following variables is as follows –

· Type of grass - Independent variable

· The mass of nitrate removed from the river: Dependent variable

· Amount of grass eaten by hippos: Dependent variable (as it impacts the grasses and hence the process of nitrate removal from river/stream water)

· The season: Co-founding Variable (as it impacts the grasses and hence the process of nitrate removal from river/stream water)

· The concentration of the nitrate in the river: Independent variable