Introduction to basic concepts of statistics

TYPES OF VARIABLES, CONTINUOUS, DISCRETE, DEPENDENT, INDEPENDENT, COLLECTION OF DATA PRIMARY SECONDARY, ERRORS, SUMMATION

1. Presented By
AFSHEEN AFFAN

2. Statisticsisthescienceofcollecting,
organizing,presenting,analyzingand
interpretingthedatatoassistin
makingmoreeffectivedecisions.
OR
Abodyofmethodsdealingwiththe
collection,description,analysisand
interpretationofinformationthatcan
begiveninnumericalform.

3. Statistics are aggregate of facts
Statistics are numerically expressed
Statistics are affected by multiplicity of
causes
Statistics are according to reasonable
standard of accuracy
Statistics are collected in a systematic
manner
Statistics are collected for a pre-
determined purpose

4. Statistics are collected in a
systematic manner
Statistics are collected for a pre-
determined purpose
Statistics must be comparable to
each other

5. “Statisticsareaggregateoffacts,
affectedtoamarkedextentbya
multiplicityofcauses,numerically
expressed,enumeratedorestimated
accordingtoareasonablestandardof
accuracy,collectedinasystematic
mannerforapredeterminedpurposeand
placedinrelationtoeachother”

6. Theoretical Statistics ( formula and
rules)
Descriptive Statistics ( numerical,
graphical, tabular forms)
Inferential Statistics ( drawing
conclusion)
Applied Statistics ( application of
statistics for policy purpose)

7. It presents facts in a numerical form
Statistics simplifies complex mass of
data
Comparison of data becomes easier
Statistics studies relationship among
different facts
Statistics studies changes in a
variable
Statistics helps forecasting

8. Business and Economics
Banks
Insurance
Sciences

9. OBSERVATION
Anything that can be measured or observed
is called an observation
DATA
Numbers or measurements that are
collected as a result of observation
POPULATION
A population is the set of all units of interest
in a particular study.

10. SAMPLE
A sample is a subset of data selected from
population.
PARAMETER
A parameter is the value associated with
population.
STATISTIC
A statistic is a value computed from a
sample.

11. Variable
Avariableisaphenomenonthatmayvary
fromoneindividualorobjecttoanothere.g.
heightofstudentsinyourclassetc.
Constant
Aquantitywhichisfixediscalledaconstant
e.g.no.ofdaysinaweek,no.ofmonthsin
ayearetc.

12. QuantitativeData
Quantitativedataareobservations
measuredonnumericalscalee.g.Dataof
heights,weights,marksetc.
QualitativeData
Qualitativedataareobservationsthatare
non-numericale.g.dataofbeauty,
intelligenceetc.wedon’thavescaleto
measurethem.

13. DiscreteData
Datawhosepossiblevaluesarecountableis
calleddiscretedatae.g.dataofprices,
incomesetc.
ContinuousData
Datawhose possiblevaluesare
uncountableandwhichmayassumeany
valueinanintervaliscalledcontinuousdata
e.g.recordoftemperatureetc.

14. Quantitativevariable
Whenthevariabletobestudiedcanbe
reportednumerically,thevariableiscalled
quantitativevariablee.g.marksintestof
statisticsetc.
Qualitativevariable
Whenthecharacteristicbeingstudiedcan
notberecordedinnumericalform,itis
calledaqualitativevariablee.g.intelligence,
genderetc.

15. DiscreteVariables
Adiscretevariableisonethatcanassume
onlycertainvalueswithinanintervale.g.
priceofriceetc.
ContinuousVariable
Acontinuousvariablecantakeonall
possiblevalueswithinaspecifiedrangee.g.
speedometerofcar,temperatureetc.

16. IndependentVariable
Avariableiscalledindependentvariableifit
isnotinfluencedbyanyothervariablee.g.
priceofpotatoes.
Dependentvariable
Avariablethatisbeingpredictedor
estimatediscalleddependentvariablee.g.
quantitydemandedofpotatoesisdependent
variablebecauseitdependsonpriceof
potatoes.

17. Primary Data ( first hand data)
Direct personal observation
Indirect personal investigation
Questionnaire method
Collection through enumerators
Collection through local sources
Secondary Data ( processed data)
Official statistics
Semi official

18. Biased Error
Unbiased Error

19. Accuracy
Significant Figures
Rounding Off Figures
Multiplication
Inequalities
Approximation
Limits
Modulus
Factorials

20. The operation of summation is symbolized
by the use of greekcapital letter Σ.
σ
??????=1
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�
??????=�
1+�
2+�
3+⋯+�
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Some other notations
❑Σ�
2
→ means square each value of X, and
then sum
❑Σ�
2
→ means sum the values of X and
then square the total
❑Σ�−3→ means subtract 3 from each
value of X , and then sum
❑Σ��→ means multiply each value of X and
Y and then add

21. THE END