You don't have to agree with all of my chosen quotations, and in this instance I disagree with my former supervisor. At the least, statistical treatment of data can help to convince yourself, and perhaps others too, of the reliability of your conclusions. Statistics are also important in cricket and bridge.

Often one repeats an estimation (notably of an enzymic activity) several times, and then reports the average result (the mean) and its standard deviation (that is, an indicator of how much the results scatter about the average). This is a descriptive use of statistics. A predictive use occurs when assessing the probability that two means (such as the activities of an enzyme in organisms grown under two conditions) are really different. In this chapter we shall see how to work out a standard deviation, and how to compare means. Going beyond these procedures (which are not all that simple) soon leads to a call for the services of a professional statistician, and damn the expense! It's like going to law.

Even determining the mean and its standard deviation is not straightforward because we have to take into account whether a mean is calculated from a whole population or from a sample of a population, and also whether the total number of individual values that contribute to a mean are small (in practice less than 30) or large (≥30).