statistics i.. course materials lecture notes coospace

Statistics I.

Course materials

Lecture notes

Coospace

http://www2.eco.u-szeged.hu/stat/

Contacts

Room 316Email: kovacs.peter@eco.u-szeged.hu Coospace

kazar.klara@eco.u-szeged.hu

Parts of Exam

Seminar: 2 computer based test

Colloquium Written exam in two parts

Introductions, notes

Statistics and other subjectsIT and StatisticsHow can you learn?Interactive lessons

Aims

Improve your statistical literacyIn the case of a given problem

Identify the applicability of statistics as a way of solution

Identify the applicable statistical methods

Interpretation of the data and results

Topics Semester 1 Descriptive statistics Comparison of data Time series

Semester 2 Inferential statistics

Hypothesis, regression, etc.

Basic terms

What are the aims and objects of statistics?Where can we encounter in statistics?What is the importance of statistics?

Who Uses Statistics?

Statistical techniques are used extensively by marketing, accounting, quality control, consumers, professional sports people, hospital administrators, educators, politicians, physicians, etc...

What is Meant by Statistics?

Statistics is the science of collecting, organizing, presenting, analyzing, and interpreting numerical data to assist in making more effective decisions.

Examination of mass phenomenon

Steps of Statistical analysis

Population or sampleA population is a collection of all possible individuals, objects, or measurements of interest.

A sample is a portion, or part, of the population of interest

registersList of the individuals

For instance

Economic unitsAdministrative units

Properties of the individuals: variables

- What is the codomain?

•For example:• Gender: male or female

• weight• 1,2,3,…,50,….kg• -10; 11-20; 21-30, …

Summary of Types of Variables

C h a rt T it le

Q u a lita tive o r a ttrib u te o r ca te g orica l(typ e o f ca r o w n e d)

d isc re te(n u m b e r o f ch ild re n)

co n tin uo us(tim e ta ke n fo r an e xa m )

Q u a ntita tive o r n u m e rica l

D A T A

Levels of measurement

Categorical Nominal Ordinal

Noncategorial, quantitative (metric, scale) Interval Ratio

Levels of Measurement

Nominal level: Data that is classified into categories and cannot be arranged in any particular order.

EXAMPLES: eye color, gender, religious affiliation.

Levels of MeasurementOrdinal level: involves data arranged in some order, but the differences between data values cannot be determined or are meaningless.

EXAMPLE: During a taste test of 4 soft drinks, Mellow Yellow was ranked number 1, Sprite number 2, Seven-up number 3, and Orange Crush number 4.

Levels of MeasurementInterval level: similar to the ordinal level, with the additional property that meaningful amounts of differences between data values can be determined. There is no natural zero point.

EXAMPLE: Temperature on the Fahrenheit scale.

Levels of Measurement

Ratio level: the interval level with an inherent zero starting point. Differences and ratios are meaningful for this level of measurement.

EXAMPLES: Monthly income of surgeons, or distance traveled by manufacturer’s representatives per month.

Types of StatisticsDescriptive Statistics: Methods of organizing, summarizing, and presenting data in an informative way.

Nominal level: tables, graph, modeOrdinak level: tables, graph, mode, medianQuantitative variable: tables, graphs, mode, median, mean, dispersion, skewness

Types of Statistics

Inferential Statistics: A decision, estimate, prediction, or generalization about a population, based on a sample.

Comparison of data

DifferenceRatio

Problems: percent/ percentage point

Tables and chartsAim: Compress the information

1. Tables

2. Charts

Formal requiremets

titleUnits, titles of rows and columnssumData sourcenotices

Order of categories?

Charts

• Scatter• Line

• Bar• Pie• Pictogram• Cartogram

Scatter

Forrás: saját szerkesztés

Line

Radius Eljárás innovációt folytató vállalkozások körében az innováció típusok aránya a különböző nemzetgazdasági ágakban, 2008

Forrás: KSH adatok alapján saját szerkesztés

Bar Chart

A bar chart can be used to depict any of the levels of measurement (nominal, ordinal, interval, or ratio).

Example3EXAMPLE 3: Construct a bar chart for the number of unemployed per 100,000 population for selected cities during 2001 City Number of unemployed

per 100,000 population Atlanta, GA 7300 Boston, MA 5400 Chicago, IL 6700

Los Angeles, CA 8900 New York, NY 8200

Washington, D.C. 8900

Bar Chart for the Unemployment Data

7300

54006700

89008200

8900

0

2000

4000

6000

8000

10000

1 2 3 4 5 6

Cities

# u

nem

plo

yed

/100

,000

Atlanta

Boston

Chicago

Los Angeles

New York

Washington

Pie Chart

A pie chart is useful for displaying a relative frequency distribution. A circle is divided proportionally to the relative frequency and portions of the circle are allocated for the different groups.

EXAMPLE 4 continued

Type of shoe # of runners

Nike 92

Adidas 49

Reebok 37

Asics 13

Other 9

EXAMPLE 4: A sample of 200 runners were asked to indicate their favorite type of running shoe. Draw a pie chart based on the following information.

Pie Chart for Running Shoes

Nike

Adidas

ReebokAsics

Other

Nike

Adidas

Reebok

Asics

Other

Pictogram

1 unit=1000 pigs

Pigs in a farm(2011)

Cartogram

Forrás: OMSZ

Heatmap of Hungary (2010.09.02. 14:00) °C

Forrás: Eurostat