Microsoft Office Tutorials and References
In Depth Information
and interval ), whether it is in dollars or some other quantitative measure, to inform
and influence an audience. In Chaps. 4 and 5 we will acknowledge that not all data
are numerical by focusing on qualitative ( categorical/nominal or ordinal ) data.
The process of data gathering often produces a combination of data types, and
throughout our discussions it will be impossible to ignore this fact: quantitative and
qualitative data often occur together.
Unfortunately, the scope of this topic does not permit in depth coverage of
the data collection process, so I strongly suggest you consult a reference on data
research methods before you begin a significant data collection project. I will make
some brief remarks about the planning and collection of data, but we will gener-
ally assume that data has been collected in an efficient and effective manner. Now,
let us consider the essential ingredients of good data presentation and the issues
that can make it either easy or difficult to succeed. We will begin with a general
discussion of data: how to classify it and the context or orientation within which
it exists.
2.2 Data Classification
Skilled data analysts spend a great deal of time and effort in planning a data collec-
tion effort. They begin by considering the type of data they can and will collect in
light of their goals for the use of the data. Just as carpenters are careful in selecting
their tools, so are analysts in their choice of data. You cannot ask a low precision
tool to perform high precision work. The same is true for data. A good analyst is
cognizant of the types of analyses they can perform on various categories of data.
This is particularly true in statistical analysis, where there are often rules for the
types of analyses that can be performed on various types of data.
The standard characteristics that help us categorize data are presented in
Table 2.1. Each successive category permits greater measurement precision and
also permits more extensive statistical analysis. Thus, we can see from Table 2.1
that ratio data measurement is more precise than nominal data measurement. It is
important to remember that all these forms of data, regardless of their classification,
are valuable, and we collect data in different forms by considering availability and
our analysis goals. For example, nominal data are used in many marketing studies,
while ratio data are more often the tools of finance, operations, and economics; yet,
all business functions collect data in each of these categories.
For nominal and ordinal data, we use non-metric measurement scales in the form
of categorical properties or attributes. Interval and ratio data are based on metric
measurement scales allowing a wide variety of mathematical operations to be per-
formed on the data. The major difference between interval and ratio measurement
scales is the existence of an absolute zero for ratio scales and arbitrary zero points for
interval scales. For example, consider a comparison of the Fahrenheit and Celsius
temperature scales. The zero points for these scales are arbitrarily set and do not
indicate an “absolute absence” of temperature. Similarly, it is incorrect to suggest
that 40 Celsius is half as hot as 80 Celsius. By contrast, it can be said that 16
Search JabSto ::

Custom Search