Effectiveness of insecticide

Use this example to explain that we are more interested in the population proportion of beetles dying — the proportion that would die if the insecticide was used on an infinitely large group of similar beetles — than the proportion dying in this specific sample.

Our single sample (and in particular the sample proportion, p = 0.72) provide information about the unknown population proportion.

The data are not real, but the context is an experiment in which fifty beetles were sprayed with a weak concentration of insecticide. We record the proportion dying.