Section 1.1 Introduction
To compute your final grade in a class your teacher will likely consider the scores you have earned on various assignments and examinations completed during the duration of the course. However, she ultimately will likely be required to assign some numerical score indicating your level of success in the course. One grade to rule them all. This final grade can only be one value and it would make sense that the grade be a reflection of your work on these tasks. So, what is a fair way for your teacher to complete this task?
Through this process, you will also often need to take into account whether that data set is the entire list of possibilities--known as the population--or just a subset of that population perhaps obtained by taking repeated measurements --that is, a sample.
In general, it is often useful to make decisions using quantitative data but making those decisions can be somewhat arbitrary without a mathematical basis supporting those decisions. In this chapter, you will consider a number of ways to use point values to represent a given set of data. Each of these quantitative metrics will be called a "statistical measure" and will, in some fashion, describe using one number some property of the entire data set. Such measures are part of what is known as "descriptive statistics". Later, you will learn about how other metrics can be used to predict properties of the underlying situation. Doing this is part of what is known as "inferential statistics".
So, let's go and hopefully you will in some measure enjoy the ride!