Introduction to STATISTICS
Statistics is the scientific study of numerical data based on natural phenomena. Statistics draw conclusions about very large groups of individuals (animate or inanimate), when we can only study small groups of them. This means that the sample of individuals being studied must be representative, in sufficient quantities, and we must also state how confident we are that the representative studied group is like the whole group. We are limited to studying a small number of individuals from a large group (population) because of time, resources and practicality.
The usefulness of statistics is in the planning and execution i.e experimental design. By the time you are inputting your data into the computer, you have already made most of the mistakes you are likely to make because chances are that a computer will do all your calculations for you. We can count on the integrity and strong sense of conscience of most scientists. This same attitude is needed to carry out an appropriate statistical analysis.
The statistical technique used to analyze data must be valid and checks are made on the data to discover whether a particular method can be applied validly. You should familiarize yourself with what a test is actually testing and then check ‘limitations and assumptions’ associated with the usage of the statistical method, before usage.