Question

An experiment tests whether insect prefer dark or bright environment. A chamber has light intensity gradient from one end (dark) to other (bright).

experimental hypothesis: “There will be a large difference between the number of insect in dark side and the number in bright side.”

for each of the following are they potential confounding variables?

A- Varying humidity across the chamber
B- The orientation of the chamber
C- The age of the insects
D- The non-reflective material from which the chamber is made
E- The type of light source used
F- Varying temperature across the chamber

Answer 1

What is a confounding variable?

http://www.biostathandbook.com/confounding.html

A confounding variable is a variable, other than the independent variable that you're interested in, that may affect the dependent variable. This can lead to erroneous conclusions about the relationship between the independent and dependent variables. You deal with confounding variables by controlling them; by matching; by randomizing; or by statistical control.

Answer 2

Yes, I think A + F could be confounding variables

probably not B + D + E

B does not change across the chamber
D is irrelevant
E is also irrelevant

probably not C, this does not change across the chamber

thoughts?

Answer 3

Yes C does not change across the chamber.

Answer 4

A + F = yes

perhaps also "B - The orientation of the chamber"

since this could change between one end of the chamber and the other?

? thoughts? orientation = up/down?