STATISTICS- AN INTRODUCTION
- It refers to numerical facts.
- It also signifies the method or methods of dealing with numerical facts.
- It refers to summarised figures of numerical facts.
DEFINITIONS:
"Statistics is the science and art that gathers and corodinates
numerous fact within a determined fied, treats these mathemetically
so that the numerical relation between these facts may be displaced
by clearly and freed from anomalies and chance factors." -English
and English
"Statistics comprise the collection, tabulation, presentation and
analysis of an aggregate of facts, collected in a methodical ,
without bias and related to a predetermined purpose."- WG
Sutcliffe
"Statistic is a branch of cientific methodology. It deal with
collection, classification, description, and interpretation of data
obtained by the conduct of urvey and experiments. Its esential
purpose is to describe and draw infernces about the numerical
properties of the populations." -George Ferguson.
TYPES OF STATISTICS:
- Theoretical statistic
- Descriptive statistics
- Inferrential statitics
- Applied statistics
- Predictive statistics
Descriptive statistics:
Descriptive statistics consist of methoids for organizing
displaying and desribing data by using table, graphs and summary
measures.
Inferential Statistics:
Inferential statistics is a process of describibg the population
based on the sample results.
Statistics are the most important tool in the hand of researhers,
which enable them to make inferences or generalizations about a
population with known possibility of errors. On the bais of
observation of the charecterstic of popolation. Such inferences are
called statistical inferences. Any statistical analysis on the
ohter hand if we deal with a sample our analyis relates not only
to the characterstic of the sample but it also provides information
about the population. such statistics or inducive statistic or
sampling statistics.
LEVEL OF MEASUREMENT
There are four levels of measurement-
- Nominal
- Oridnal
- Interval
- Ratio
Nominal
It is a primitive type of measurement in which we adopt a general
rule:
Do not assign the same numeral/ symbol to different objects,
individuals or classes or different numerals /symbols to same
object, individuals or class.
Thus in nominal scale numbering or classification is always made
according to the similarity or difference observed with respect to
some charaterstic or property.For example if we take eye color as a
variable, then we will be able to:
a) Classify the individuals in categories like- blue eyed, green
eyed or black eyed.
b) Further identify them as individuals by assingnig them with
numbers/ symbols within each category.
Ordinal scale
Here the numbers reflect their rank order or merit
position within their own group or class with espct to some
quality, property or performance. A ordinary example of such a
scale is ordering or ranking the students of a class as I,II,III
based on marks ontained by them on achievement test. Here large
score reflect more of the quality or characterstics on the basis of
which the individuals are ordered in ranks.
The defect of this scale or kind of measurement lies in the fact
that the units along the scale are of unequal size.
Interval scale
This kind of measurement not only assigns rank or oder but points
out the relative qualitative as well as quantitative difference.
The major strength of this scale lies in the fact that they have
equal units of measurement. However they do not posses a true zero.
Example : Farenhiet or centigrade scale here the zero does not
indicate the absence of heat.
Ratio measurement
Here the measures are not only expressed in equal unit but true
zero also exists. The zero here indicates absence of quality or
attribute bieng asessed. Example are measurement of hieght ,
length, wieght etc. These permit statements regarding the
comparative ration in relation to some quality or property existing
among different individuals. Such type measurement is used in
Physical sciences.
