Bài giảng nguyên lý thông kê chương 1 introduction to statistics lecturer

Lecturer: DAO MINH ANH
Faculty of Business and Administration
Foreign Trade University
Email:


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Textbook
Business Mathematics and Statistics – 5th
edition (A. Francis)
References:
Essentials of Statistics for Business and
Economics – 3rd edition, 2003 (Anderson
Sweeney Williams)
Statistics for Business and Economics – 4th
edition (Paul Newbold)


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Class attendance: 10%
Group Assignment and presentation: 30%

Final exam: 60%



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Tracking information: sales, inventory, products
being transported, refunded items, customer information
(demographic), business performance of suppliers, etc.
Collecting
and
analyzing
data
“Market
basket”

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Decision making on:
- Future trend
- Inventory Management
- Customer Relationship Management...


I.

What is statistics?

II.

Definitions

III.

Descriptive statistics and Inferential
statistics

IV.

Qualitative and Quantitative data

V.

Scales of Measurement


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What first appear in your mind when we talk
about “statistics”?
interest rates, population, stock market
prices, unemployment…
- In a very general way:
Statistics

numerical information

- Furthermore:
Statistics

Statistical methods
- Collect
- describe
- summarize
- present
- analyze


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Making sense of numerical information
Dealing with uncertainty
Sampling
Analyzing relationships
Forecasting
Decision making in an uncertain
environment


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In order to make the right decision or

forecast, decision-makers require as much
information as possible.

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However, after being collected numerical
information is under the raw form.
impossible to comprehend thoroughly

These information need to be summarized, organized and
analyzed so that important features emerges


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“Statistics is the science of uncertainty”
In statistics we have to deal with the
question what might be, what could be…
not what is
One task of statistics is to estimate the
level of uncertainty


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E.g: Before bringing a new product to
market, market research survey about the

likely level of demand of this product maybe
should the survey cover all potential buyers
undertaken?
(population)?
Absolutely impossible due
to the huge costs of time,
money, people…

Sampling


Let’s consider some examples below:
(i) Does the growth rate of money supply
influence the inflation rate?
(ii) If the price of a product rise by 5%, what is
the effect on the sales of this product?
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- The relationships between variables will be
analyzed in a quantitative way not qualitative
way based on the past behaviors of these
variables


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Reliable predictions play a key role in
management and making decision
For example: investment decisions must be
made well ahead of the time at which a new
product can be brought to market;
Essentially, forecasts of future values are
obtained through the information of past
behaviors
The analysis of this information suggests
future trend


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A particular problem for management:
making decisions in the condition of
incomplete information

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Therefore, under such circumstances,
possible options should be raised and
considered


Accounting

Public accounting firms use
statistical sampling procedures

when conducting audits for their
clients.
Economics
Economists use statistical
information in making forecasts
about the future of the economy
or some aspects of it.


Marketing
Electronic point-of-sale scanners
at retail checkout counters are
used to collect data for a variety
of marketing research
applications.

Production
A variety of statistical quality
control charts are used to monitor
the output of a production
process.


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Finance
Financial advisors use price-earnings ratios
and dividend yields to guide their
investment recommendations.

1/ Variable is a characteristic that changes or
varies over time for different individuals or objects
under consideration
2/ Experimental Units (elements) are items or
objects on which measurements are taken
4/ Population is the WHOLE set of all items or
individuals of interest
5/ Sample is an observed subset of population
values


Population vs. Sample
Population
a b

Sample

cd

b

ef gh i jk l m n
o p q rs t u v w
x y

z

c

gi
o

n
r
y

u


Statistics

Descriptive Statistics

Inferential Statistics


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Descriptive statistics: Methods used to
summarize and describe the main features of
the whole population in quantitative term.
Tabular, graphical, and numerical methods
(mean, median, variance, standard
deviation…)
Used when we can enumerate the whole

population


- Collect data
e.g., Survey, Observation,
Experiments

- Present data
e.g., Charts and graphs
- Characterize data
e.g., Calculate mean =

∑x
n

i


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Inferential statistics: Procedures used to
draw conclusions or inferences about the
characteristics of a population from
information obtained from the sample.
Making estimates, testing hypothesis…
Used when we can not enumerate the whole
population

Population parameters
Sample statistics
(known)

Inference

Sample

(unknown, but can be
estimated from sample
evidence

Population