CHAPTER 7

Numerical Data

Are Your Statistics Normal?

When a sample consists of numerical data, it has many features that can be quantified. These features can be used to summarize the data, to provide information about the population from which the sample was obtained, and to indicate the reliability of such information. Also, the calculated properties of the sample can be used subsequently if the sample becomes part of a further investigation.

A well-known feature of a sample of numerical data is the average value. Indeed, we get a daily dose of averages from the media and from general conversation. But an average value, though having its proper uses, can be extremely misleading when quoted in isolation. A proper consideration of a data sample ...

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