business statistics lec 1

8/8/2019 Business Statistics Lec 1

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INTRODUCTION TO

STATISTICS

C

hapt

er

1



What is statistics?

Statistics is a mathematical science that isconcerned with the techniques by whichinformation (data) is collected, organized,presented, analyzed and interpreted.



application

Accounting

Finance

MarketingProduction

Economics



Business StatisticsBusiness Statistics is a science assisting you to

make good business decisions underuncertainties based on some numerical andmeasurable scales.



Data, Information & Knowledge



ELEMENTS, VARIABLES & OBSERVATIONS

Elements: Entities on which data is collected

Variable: A characteristic of interest for the elements.

Observation: The set of measurements obtained for aparticular element.



Population & Sample

Population: A population is the setrepresenting all observations of interest tothe sample collector.

Sample: A subset of measurements selectedfrom the population of interest.



Descriptive & Inferential StatisticsDescriptive Statistics consists of procedures

used to summarize the information in a setof measurements and to describe thecharacteristics of the set.

Inferential Statistics consists of theprocedures used to make inferences aboutpopulation characteristics from informationcontained in a sample.



Methods of Sampling

Convenience Samples – The most easily accessible

observations/measurements.

Judgment Samples –Individual selecting thesample items uses experience.

Random Samples – Every element of thepopulation has a known, and usually equal

chance of being chosen for inclusion in thesample.



Types of Random samples

Simple random sample - Each item is selectedentirely on the basis of chance.

Systematic sample - We select the sampleelements at a uniform interval of a listed orderor at uniform points in time or distance.

Stratified sampling can be used whenever thepopulation can be partitioned into smaller sub-populations, groups, or strata, each of which ishomogeneous according to the particularcharacteristic of interest.



Types of Random samples (cont..)Cluster Sample

Elements in the target population are selected ingroups rather than individually at the initial stepin sampling.

The groups to be included in the sample areselected by simple random sampling. Thus eachgroup in the target population is assigned aserial no.

Often used when the elements in the populationare not easily identified individually but aregrouped together (clustered) and more easilyidentified as members of the clusters.



DATA

REPRESENTATION



Types of Data

Internal & External Data

Primary and Secondary Data

Qualitative & Quantitative dataDiscrete & Continuous data



Frequency distribution

Relative Frequency distribution

Percentage frequencydistribution

BarGraph

PieChart

Frequency distributionRelative Frequency distributionPercentage frequency

distributionCFDCRFDCPFD

Histogram

Ogive

ScatterDiagram



Tabular Representation

Frequency DistributionStep 1: Determine the desired no. of classes

Step 2: Determine the class Width / ClassInterval

Step 3: Locate the Class limits or Classboundaries (true class limits)



Relative frequency distributionThe proportion of observations belonging to one

class.

Percentage frequency distributionThe percentage of observations belonging to one

class

Cumulative frequency distribution



Graphical Representation

Histogram

Frequency Polygon

Frequency Curve

OgivePie Diagram

Scatter Diagram



THANK YOU

business statistics lec 1

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