Question

Use the description below and the ‘Antioxidant enzyme dataset’ to answer question(s)

Understanding oxidative stress requires that we understand what triggers the production of antioxidant enzymes within a cell. Studies have shown that yeast cells with high levels of one antioxidant enzyme tend to also have high levels of other antioxidant enzymes.

A team of Russian scientists wondered if the enzyme superoxide dismutase (SOD) could trigger the production of catalase. To investigate this, the researchers created a gradient of SOD activity levels by exposing yeast cells to different amounts of an inhibitor of SOD. Thus, some yeast suspensions had higher SOD activity levels than others.

After culturing the yeast in YPD media for an hour, the researchers measured catalase activity (U/mg protein) and SOD activity (U/mg protein) in the various yeast suspensions.

What is the independent variable? Is this variable categorical or quantitative?

Answer 1

Remember that the independent variable is the one that we are controlling, the one that we are stablishing in each treatment, thus the dependent variable is the one that will variate according to the independent variable's values.

In this case our independent variable is kind of tricky, it is the amount of SOD inhibitor applied. This variable is quantitative, as we are talking about amounts, it is not specified, but most likely it is measured in concentration units.