Introduction

Before starting on experimental design and statistics, it is important to be familiar with how science is done. This is a summary of a very conventional view of scientific method.

Basic scientific method

The essential features of the “hypothetico-deductive” view of scientific method (see Popper,1968) are that a person observes or samples the natural world and uses all the information available to make an intuitive logical guess, called a hypothesis, about it or how it functions. The person has no way of knowing if their hypothesis is correct – it may or may not apply. Predictions made from the hypothesis are tested, either by further sampling or by doing experiments. If the results are consistent with the predictions then the hypothesis is retained. If they are not, it is rejected, and a new hypothesis formulated (Figure 2.1). The initial hypothesis may come about as a result of observations, sampling and/or reading the scientific literature.

Here is an example. Lead contamination is an enormous environmental problem because in the past many manufacturers discarded wastes containing lead and other heavy metals into pits and landfills. These heavy metals are water soluble so they can leach into aquifers, be transported by groundwater and contaminate water supplies. In the early days, clean-up of these sites involved digging up the contaminated soil and removing it to special disposal facilities where water run-off could be contained and treated.