Question

From the following table which one is the dependent and independent variable and what type of graph would you choose for this data?

(a) Dependent – Bubbles per minute Plant A, Independent- Bubbles per minute Plant B, Graph- Pie chart

(b) Dependent – Depth (in meters), Independent- Bubbles per minute Plant A, Graph- Line plot

(c) Dependent – Depth (in meters), Independent- Bubbles per minute Plant B, Graph- Line plot

(d) Dependent – Bubbles per minute Plant A and Plant B, Independent- Depth (in meters), Graph- Line plot

The question was posed to me in exam.

Question is from Graph Paper with Logarithmic Coordinates in chapter Presentation and Analysis of Data of Bioprocess Engineering

Answer 1

Correct choice is (d) Dependent – Bubbles per minute Plant A and Plant B, Independent- Depth (in meters), Graph- Line plot

Easiest explanation: Dependent variable-

Bubbles per minute – the amount of bubbles produced will depend on how deep the plant is in the water. The variable that DEPENDS on another variable is the dependent variable.

Independent variable-

The depth in meters – you are controlling the depths at which you place the plants and observing what happens to the number of bubbles. Typically the variable you have control over is the independent variable.

Graph-

Line – we are measuring the change in bubble production over time. (Why not a bar? – There are some gradual changes that may be lost depending on our scale. Also, lines are often more simple to read and less confusing).