Statistics an introduction (1)

Statistics
Dr.Suresh Kumar Murugesan PhD

Statistics
Statistics is the discipline that concerns the collection, organization, analysis,
interpretation, and presentation of data.

Statistics: Definition
“Statistics are numerical statements of facts in any
department of enquiry placed in relation to each
other.” —A.L. Bowley
‘Statistics is the science of counting’ -A. L .Bowley

Statistics:
Definition
“The classified facts respecting
the condition of the people in a
state—especially those facts
which can be stated in
numbers or in tables of
numbers or in any tabular or
classified arrangement.” —
Webster

Statistics:
Definition
“By statistics we mean aggregates of facts affected to a marked extent by
multiplicity of causes, numerically expressed, enumerated or estimated
according to reasonable standard of accuracy, collected in a systematic
manner for a predetermined purpose, and placed in relation to each
other.”—Horace Sacrist

“Statistics refers to the body of technique or methodology, which has been
developed for the collection, presentation and analysis of quantitative data and
for the use of such data in decision making.” —Ncttor and Washerman

Statistics:
Definition
“Statistics may rightly be called the science of averages.” —
Bowleg

“Statistics is a body of methods for making wise decisions on the face of
uncertainty.” —Wallis and Roberts

“Statistics is a body of methods for obtaining and analyzing numerical data in
order to make better decisions in an uncertain world.” —Edward N. Dubois

“Statistics may be defined as the collection, presentation, analysis, and
interpretation of numerical data.” —Croxton and Cowden

Ya-Lun-Chou slightly modifies Wallist and
Roberts definition and come with the following
definition : “Statistics is a method of decision
making in the face of uncertainty on the basis
of numerical data and calculated risk.”

Statistics
“Statistics in the sense of data are numerical statements
of facts capable of analysis and interpretation”.
“Statistics in the sense of science is the study of principles
and methods used in the collection, presentation, analysis
and interpretation of numerical data in any sphere of
enquiry”.

Parameter Vs Statistics
1. Parameters are numbers that summarize data for an entire
population.
2. Statistics are numbers that summarize data from a sample, i.e. some
subset of the entire population.

Parameter vs. Statistics
● A parameter is a fixed measure describing the whole population
(population being a group of people, things, animals, phenomena that
share common characteristics.) A statistic is a characteristic of a sample, a
portion of the target population.
● A parameter is a fixed, unknown numerical value, while the statistic is a
known number and a variable which depends on the portion of the
population.
● Sample statistic and population parameters have different statistical
notations

Characteristics of
Statistics
(1) Aggregate of facts collected in
systematic manner for a specific purpose.
Statistics deals with the aggregate of facts and
figures. A single number cannot be called as
statistics. For example, the weight of a person
with 65kg is not statistics but the weights of a
class of 60 persons is statistics, since they can
be studied together and meaningful
comparisons are made in relation to the other.
This reminds us of Joseph Stalin’s well known
quote, “One death is a tragedy; a million is a
statistics.” Further the purpose for which the
data is collected is to be made clear, otherwise
the whole exercise will be futile. The data so
collected must be in a systematic way and
should not be haphazard.

Characteristics of Statistics
(2) Affected by large number of causes to marked extent.
Statistical data so collected should be affected by various factors at the same
time. This will help the statistician to identify the factors that influence the
statistics. For example, the sales of commodities in the market are affected by
causes such as supply, demand, and import quality etc. Similarly, as mentioned
earlier if a million deaths occur the policy makers will be immediately in action to
find out the causes for these deaths to see that such events will not occur.

(3) Numerically expressed.
The statistical facts and figures are collected numerically for meaningful inference. For instance,
the service provided by a telephone company may be classified as poor, average, good, very good
and excellent. They are qualitative in nature and cannot be called statistics. They should be
expressed numerically such as 0 to denote poor,1 for average, 2 for good, 4 to denote very good
and 5 for excellent. Then this can be regarded as statistics and is suitable for analysis. The other
types of quality characteristics such as honesty, beauty, intelligence, defective etc which cannot be
measured numerically cannot be called statistics. They should be suitably expressed in the form of
numbers so that they are called statistics.

(5) To be placed in relation to the other.
One of the main reasons for the collection of statistical data is for comparisons In order to make
meaningful and valid comparisons, the data should be on the same characteristic as far as
possible. For instance, we can compare the monthly savings of male employees to that of the
female employees in a company. It is meaningless if we compare the heights of 20 year-old boys
to the heights 20 year- old trees in a forest.

(4) Enumerated or estimated with a reasonable degree of accuracy.
The numerical data are collected by counting, measuring or by estimating. For example, to find out
the number of patients admitted in a hospital, data is collected by actual counting or to find out the
obesity of patients, data are collected by actual measurements on height and weight.
In a large scale study like crop estimation, data are collected by estimation and using the powerful
sampling techniques, because the actual counting may or may not be possible. Even if it is
possible, the measurements involve more time and cost. The estimated figures may not be
accurate and precise. However certain degree of accuracy has to be maintained for a meaningful
analysis.

S.NO Functions What it does
1 Collection The basic ingredient of statistics is data. It should be carefully and
scientifically collected
2 Classification The collected data is grouped based on similarities so that large and
complex data are in understandable form.
3 Condensation The data is summarized, precisely without losing information to do
further statistical analysis.
4 Comparison It helps to identify the best one and checking for the homogeneity of
groups,
5 Correlation It enables to find the relationship among the variables
6 Causation. To evaluate the impact of independent variables on the dependent
variables.
7 Chance Statistics helps make correct decisions under uncertainty.
Functions of Statistics (7C’s)

Statistics: Functions
1. To Present Facts in Definite Form
2. Precision to the Facts
3. Comparisons
4. Formulation and Testing of Hypothesis
5. Forecasting
6. Policy Making
7. It Enlarges Knowledge
8. To Measure Uncertainty:

1. To Present Facts in
Definite Form:
We can represent the things in their true form with the help
of figures. Without a statistical study, our ideas would be
vague and indefinite.
The facts are to be given in a definite form. If the results are
given in numbers, then they are more convincing than if the
results are expressed on the basis of quality.
The statements like, there is lot of unemployment in India or
population is increasing at a faster rate are not in the
definite form. The statements should be in definite form like
the population in 2004 would be 15% more as compared to
1990.

2. Precision to the Facts:
The statistics are presented in a definite form so they also help in
condensing the data into important figures. So statistical methods present
meaningful information. In other words statistics helps in simplifying
complex data to simple-to make them understandable.
The data may be presented in the form of a graph, diagram or through an
average, or coefficients etc. For example, we cannot know the price
position from individual prices of all good, but we can know it, if we get the
index of general level of prices.

3. Comparisons:
After simplifying the data, it can be correlated as well as compared. The
relationship between the two groups is best represented by certain mathematical
quantities like average or coefficients etc. Comparison is one of the main functions
of statistics as the absolute figures convey a very less meaning.

4. Formulation and Testing
of Hypothesis:
These statistical methods help us in formulating and testing the
hypothesis or a new theory. With the help of statistical techniques, we
can know the effect of imposing tax on the exports of tea on the
consumption of tea in other countries. The other example could be to
study whether credit squeeze is effective in checking inflation or not.

5. Forecasting:
Statistics is not only concerned with the above functions, but it also predicts the
future course of action of the phenomena. We can make future policies on the
basis of estimates made with the help of Statistics. We can predict the demand for
goods in 2005 if we know the population in 2004 on the basis of growth rate of
population in past. Similarly a businessman can exploit the market situation in a
successful manner if he knows about the trends in the market. The statistics help
in shaping future policies.

6. Policy Making:
With help of statistics we can frame favourable
policies. How much food is required to be imported
in 2007? It depends on the food-production in
2007 and the demand for food in 2007. Without
knowing these factors we cannot estimate the
amount of imports. On the basis of forecast the
government forms the policies about food grains,
housing etc. But if the forecasting is not correct,
then the whole set up will be affected.

7. It Enlarges Knowledge:
Whipple rightly remarks that “Statistics enables one to
enlarge his horizon”. So when a person goes through
various procedures of statistics, it widens his knowledge
pattern. It also widens his thinking and reasoning power.
It also helps him to reach to a rational conclusion.

8. To Measure Uncertainty:
Future is uncertain, but statistics help the various authorities in all the
phenomenon of the world to make correct estimation by taking and analyzing the
various data of the part. So the uncertainty could be decreased. As we have to
make a forecast we have also to create trend behaviors of the past, for which we
use techniques like regression, interpolation and time series analysis.

Statistics: Scope and Application
● Actuarial science,
● Commerce,
● Economics,
● Medicine,
● Agriculture,
● Industry,
● Information Technology
● Government

Statistics Uses in Research
1. Statistics helps in providing a better understanding and exact description of a phenomenon of
nature.
2. Statistics helps in the proper and efficient planning of a statistical inquiry in any field of study.
3. Statistics helps in collecting appropriate quantitative data.
4. Statistics helps in presenting complex data in a suitable tabular, diagrammatic and graphic form for
easy and clear comprehension of the data.
5. Statistics helps in understanding the nature and pattern of variability of a phenomenon through
quantitative observations.
6. Statistics helps in drawing valid inferences, along with a measure of their reliability about the
population parameters from the sample data.

References
1. https://whatagraph.com/blog/articles/parameter-vs-statistic
2. Pooja Mehta (). https://www.economicsdiscussion.net/essays/essay-on-
statistics-meaning-and-definition-of-statistics/2315
3. https://www.emathzone.com/tutorials/basic-statistics/functions-or-uses-of-statistics.htm
4. https://www.economicsdiscussion.net/statistics/8-functions-of-statistics-
scope-and-importance/2325

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