CHAPTER 1: WHAT IS STATISTICS?
1.1 AN OVERVIEW OF STATISTICS
DEFINITION 1.1:
STATISTICS
Statistics
is the science of learning from data. This means that
statistics
is a method of
extracting information from data. It involves rules and procedures for collecting (by
statistical surveys), classifying, summarizing, presenting (in tabular or graphical form; or
by summary statistics), analyzing and interpreting
numerical information
to assist in
making prompt and more effective decisions when faced with uncertainty.
The work of the statistician is no longer confined to gathering and tabulating data, but is
chiefly a process of interpreting the information and making predictions. In making
predictions,
statistics
uses the companion subject of
probability
. The development of the
theory of probability increased the scope of statistical applications. Many data can be
approximated accurately by certain probability distributions, and the results of probability
distributions can be used in analyzing statistical data. Probability can be used to test the
reliability of statistical inferences and to indicate the kind and amount of data required for
a particular problem.
Today,
statistics
has become an important tool in the work of many academic disciplines
such as
medicine
,
psychology
,
education
,
sociology
,
engineering
and
physics
, just to
name a few. Statistics is also important in many aspects of society such as
business
,
industry
and
government
. Because of the increasing use of statistics in so many areas of
our lives, it has become very desirable to understand and practice statistical thinking.
This is important even if you do not use statistical methods directly.
1.2 EXPERIMENTAL UNIT and TYPES OF VARIABLE
DEFINITION 1.2:
EXPERIMENTAL UNIT
An
experimental unit
(or
observational unit
) is an object or individual (
e.g.
, thing,
transaction, event, activity, or person, or some unified group or institution) upon which
we collect data either in an
experiment
or in an
observational study
, respectively. When
an
experimental unit
(or
observational unit
) deals with
human beings
,
experimental
units
(or
observational units
) are called
subjects
or
participants
.
Dr. LOHAKA – QBA 2302 Chapter 1:
WHAT IS STATISTICS?
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