Suppose a researcher wants to determine the tensile strength of pieces of copper wire (i.e. how much weight a piece of wire can lift without breaking) at three different temperatures (20, 50, and 200 degrees Celsius). To this end, 30 pieces of wire were obtained, each piece of wire was randomly placed into a temperature group, and the tensile strength was measured.

(a) Is this an experiment or observational study? Why? (b) What is the response variable?

(c) What is the explanatory variable?

(d) Is it likely that this study will suffer from problems with confounding variables?

Why?