Question

o check the effect of cold temperature on the elasticity of two brands of rubber bands, one box of Brand A and one box of Brand B rubber bands are tested. Ten bands from the Brand A box are placed in a freezer for two hours and ten bands from the Brand B box are kept at room temperature. The amount of stretch before breakage is measured on each rubber band, and the mean for the cold bands is compared to the mean for the others. Is this a good experimental design?

Answer 1

Answer:

No this is a not good experimental design

Step-by-step explanation:

In an experiment, we seek to establish cause an effect relationship. The effect of one variable on another is examined while keeping other variables constant. A control often establishes the validity of the experiment.

Now the ten rubber bands were selected at random from each box. The experimental group was put in a freezer while the control group was maintained at room temperature.

Comparison of the mean stretch before breakage of the rubber bands in both groups establishes the effect of cold temperature on elasticity of rubber bands.

However, this is not a good experimental design because the sample rubber bands should have been picked from different boxes of brand A and B and not from the same box.

Secondly, samples from the two brands should have been put in the freezer and kept at room temperature. That is, ten rubber bands from A are put on the freezer and another 10 are left at room temperature. 10 rubber bands from B are put in the freezer and another 10 are left at room temperature.

The mean elasticity of the both groups can now be meaningfully compared from the data obtained.