collection of statistical data

8/7/2019 collection of statistical data

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Collection

Of

Statistical

Data.


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decisions on some characteristics of the entirepopulation based on a representative part/sample of itis a huge advantage, both in terms of cost andmanagement, without sacrificing accuracy and

efficiency of the results. In reality, often that is the onlyrealistic choice.

Some scholars pinpoint the origin of statisticsto 1663, with the publication of Natural andPolitical Observations upon the Bills of Mortalityby John Graunt. Early applications of statisticalthinking revolved around the needs of states to basepolicy on demographic and economic data, hence itsstat- etymology. The scope of the discipline ofstatistics broadened in the early 19th century toinclude the collection and analysis of data in general.

Today, statistics is widely employed in government,business, and the natural and social sciences.

Statistics mathematical foundations werelaid in the 17th century with the development of

probability theory by Blaise Pascal and Pierre deFermat. Probability theory arose from the study ofgames of chance. The method of least squares wasfirst described by Carl Friedrich Gauss around1794.

The use of the word Statistics is believed to havebeen made for the first time by German Scholar

Gottfried Achen Well (1719-1772 A.D.).JohnSinclair also used the word Statistics in his book. InEncyclopaedia Britanika of 1797, there alsoreferences about Statistics. Indian contribution in thefield of Statistics has been quite significant fromancient times.
http://en.wikipedia.org/wiki/John_Graunthttp://en.wikipedia.org/wiki/History_of_statistics#Etymologyhttp://en.wikipedia.org/wiki/Probability_theoryhttp://en.wikipedia.org/wiki/Blaise_Pascalhttp://en.wikipedia.org/wiki/Pierre_de_Fermathttp://en.wikipedia.org/wiki/Pierre_de_Fermathttp://en.wikipedia.org/wiki/Method_of_least_squareshttp://en.wikipedia.org/wiki/Carl_Friedrich_Gausshttp://en.wikipedia.org/wiki/History_of_statistics#Etymologyhttp://en.wikipedia.org/wiki/Probability_theoryhttp://en.wikipedia.org/wiki/Blaise_Pascalhttp://en.wikipedia.org/wiki/Pierre_de_Fermathttp://en.wikipedia.org/wiki/Pierre_de_Fermathttp://en.wikipedia.org/wiki/Method_of_least_squareshttp://en.wikipedia.org/wiki/Carl_Friedrich_Gausshttp://en.wikipedia.org/wiki/John_Graunt


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In Kautilayas Arthsashtra references areavailable about the collection of statistics regardingagriculture, population and finance during MauryanEmpire. References are also available in Ain-I-Akbari

of Abdul Fazal about the collection of statistics duringthe rule ofMughal Emperor Akbar.

In Kolkata the Indian Institute of Statisticsestablished by Prof.P.C Mahalanobis gives importantcontribution in research and development of thesubject Statistics. This institute has beeninternationally recognized as a center where advancedlevel of research in the field of Statistics.

The word statistics, when referring to the scientificdiscipline, is singular, as in "Statistics is an art." Thisshould not be confused with the word statistic,referring to a quantity (such as mean or median)calculated from a set of data, whose plural is statistics,e.g. "This statistic seems wrong." or "These statisticsare misleading."

Modern Statistics has grown and developed inthree phases. The seed of Statistics was sown by kingsand rulers and its plant was nourished and nurtured bymathematicians. Finally, modern Statistics has grownin to a tree bearing flowers and fruits in the fields ofscience and commerce.

More probability density will be found the closer

one gets to the expected (mean) value in a normaldistribution. Statistics used in standardized testingassessment are shown. The scales include standarddeviations, cumulative percentages, percentileequivalents, Z-scores, T-scores, standard nines, andpercentages in standard nines.
http://en.wikipedia.org/wiki/Meanhttp://en.wikipedia.org/wiki/Medianhttp://en.wikipedia.org/wiki/Probability_density_functionhttp://en.wikipedia.org/wiki/Normal_distributionhttp://en.wikipedia.org/wiki/Normal_distributionhttp://en.wikipedia.org/wiki/Standardized_testinghttp://en.wikipedia.org/wiki/Standard_deviationshttp://en.wikipedia.org/wiki/Standard_deviationshttp://en.wikipedia.org/wiki/Meanhttp://en.wikipedia.org/wiki/Medianhttp://en.wikipedia.org/wiki/Probability_density_functionhttp://en.wikipedia.org/wiki/Normal_distributionhttp://en.wikipedia.org/wiki/Normal_distributionhttp://en.wikipedia.org/wiki/Standardized_testinghttp://en.wikipedia.org/wiki/Standard_deviationshttp://en.wikipedia.org/wiki/Standard_deviations


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Statistics is a science in which data collectedby either conducting experiments or inquires ofdifferent phenomena and events are classified,tabulated and analysed by mathematical

methods in order to explore, explain andcompare the inherent nature of thesephenomena and events.

A universally accepted definition ofStatistics can be given as follows:-

The science of Statistics in the study ofmathematical methods used in collection,

presentation, analysis, drawing conclusionsbased on mutually related numerical data withpre-determined objective by conducting aninquiry or experiment subjected to differentforces of natural and / or other relevantphenomena.

The above definition is based on the use ofnumerical data, but study of qualitative data is also

done in statistics.

Statistics is the science of the collection,organization, and interpretation of data. It dealswith all aspects of this, including the planning ofdata collection in terms of the design ofsurveysand experiments.

Statisticians improve the quality of data with the

design of experiments and survey sampling. Statisticsalso provides tools for prediction and forecasting usingdata and statistical models. Statistics is applicable to awide variety ofacademic disciplines, including naturaland social sciences, government, and business.
http://en.wikipedia.org/wiki/Survey_samplinghttp://en.wikipedia.org/wiki/Experimental_designhttp://en.wikipedia.org/wiki/Design_of_experimentshttp://en.wikipedia.org/wiki/Survey_samplinghttp://en.wikipedia.org/wiki/Statistical_modelhttp://en.wikipedia.org/wiki/Academic_disciplinehttp://en.wikipedia.org/wiki/Naturalhttp://en.wikipedia.org/wiki/Social_sciencehttp://en.wikipedia.org/wiki/Survey_samplinghttp://en.wikipedia.org/wiki/Experimental_designhttp://en.wikipedia.org/wiki/Design_of_experimentshttp://en.wikipedia.org/wiki/Survey_samplinghttp://en.wikipedia.org/wiki/Statistical_modelhttp://en.wikipedia.org/wiki/Academic_disciplinehttp://en.wikipedia.org/wiki/Naturalhttp://en.wikipedia.org/wiki/Social_science


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In this age of interdisciplinary approach, statisticshas been recognized as behavioral and appliedscience. Moreover, the study of statistics is alsoconsidered as an important part of scientific methods.

Thus it goes without saying that the elementaryknowledge of basic principles of statistics has becomean integral part of part of the general educationreceived by every educated and professionalindividual.

Population survey & Sample survey.

For a Statistical inquiry or investigation of a

problem in any field, one has to collect dataconcerning the problem. The Statistical inquiry or

investigation is of two types. They are (1)

Population inquiry. (2)Sample inquiry. Better

accuracy can be achieved if information is on all units

covered under the field of inquiry.

Population survey.

Better accuracy can be achieved if information

is on all units covered under the field of inquiry. The

totality of all units covered under the field of inquiry

or investigation is called a Population. The total

number of units contained in the population inquiry or

investigation is called the size of the population. If

the number of units in the population is finite, thenthe population is called finite population with size

N. If the number of units in the population is infinite,

then the population is called infinite population

with size N. In real life situation we deal with we think


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of only finite population. If we take group of students

as population then the unit of population is student. If

we take group of family as population then the unit of

population is family. If we take group of Electric bulb

manufactured by a factory as population then the unit

of population is Electric bulb. Thus interpretation of a

population and its unit can be made according to

context.

An inquiry in which information on each &

every unit of the population is obtained for

inspection is called a Population inquiry orCensus inquiry. For example, the population census

conducted for every ten years in the country is the

example ofpopulation inquiry. Inquiry of all citizens of

the country is the example ofpopulation census and

the total number of citizens of the country is called

the size of the population.

If the field of inquiry or survey is veryextensive and wide, conducting a population inquiryor survey becomes difficult, if not impossible. Thetotal inquiry of all units of population requires lot ofmoney, time and energy. Moreover we require morenumber of enumerators to collect information on eachand every unit of the population. It is rather difficult toget sufficient number of experienced, honest, diligent

and clever enumerators. In some circumstancespopulation inquiry is not practically feasible therequires another inquiry that is sample inquiry.

In particular, a population inquiry provesworthless if all the units of the population after theinspection are to be destroyed. For example, if an


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inquiry of electric bulbs involves recording the life ofthe bulb till they fuse out then complete inquiry of allbulbs leaves no bulb for use. So we require sampleinquiry.

Sample survey.

The remedy of overcoming the practicaldifficulty encountered in population survey lies inselecting representative units in a scientific or random

manner and inquiry is made on these selected unitsonly. A group of such selected units is called asample, and total number of each selected units iscalled the sample size or size of the sample. A unitselected in the sample is called a sample unit. Aninquiry made on each unit of the sample is called asample inquiry or sample survey.

In our day to day life we, knowingly orunknowingly, resort to sample inquiry. For example apathologist takes a few drops of blood for medicalexamination. A housewife, while cooking, examines afew cooked grains to check whether the grains arecooked or not. A candidate appearing for personalinterview for job is asked a few questions to judge hissuitability for the job.

Sample inquiry compared to population inquiryis simple, less expensive, speedy and more practical.But the selection of a sample for this purpose requiresmeticulous care. Such a sample should be therepresentative of the population. In other words, itsselection should be done at random; size of the


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sample should not be unduly small or unduly large.For example, a sample of size 100 from a populationof 1000 families of the labour area of a city on city on10% basis can be called representative sample for

conducting a socio-economic status of these 1000families of the labour area is same a large extent,populatation of 1000 families of the labour area canbe called a homogeneous population. A populationof 1000 100 watt electric bulbs produced by a factoryon daily basis can also be called a homogeneouspopulation. Suppose we want to undertake a socio-economic survey of families of an industrial city is

called a non-homogeneous population. In order tomake this population homogenous, we requiredividing the families of the city on the basis of socio-economic status into three classes such as labourclass families, middle class families and upper classfamilies. We can take each of these classes ashomogeneous and each class may be called the subpopulation of the original population. We can conduct

the socio economic inquiry by taking a sample ofappropriate size from each of these sub population.

Sample inquiry can be either of withoutreplacement or with replacement.

It can be as follows:

While selecting a sample for a sampleinquiry, if a unit selected at any draw is not

replaced in the population before the nextdraw, then such a sample is called samplewithout replacement and inquiry is calledsampling without replacement. If a unitselected at any draw is replaced in thepopulation before the next draw, then such a


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sample is called sample with replacement andinquiry is called sampling with replacement.

Diff. Population & Sample Survey.

Population survey Sample Survey

In population survey all theunits are examined. So itrequires more time.

In sample survey fewerunits are examined. So itrequires less time.

The cost of survey is more. The cost of survey isless.

As more units are to beexamined proper accuracycannot be maintained.

Accuracy can bemaintained as few unitsare to be examined.

Population study is notpossible when the unitsare to be destroyedduring the study.

Sample study is possiblewhen the units are to bedestroyed during thestudy.

As more persons areemployed to the workexperts may not beavailable.

As few persons are to beemployed experts maybe available.

As more units are to bestudied the work becomestedious.

As few units are to bestudied the workbecomes relativelyeasy

As all units are examinedcomplete information isavailable.

Limited number of theunits are examined hencecomplete informationis not available.

As more units are to be As fewer units are to be


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examined It occupies moretime.

examined It occupiesrelatively less time.

Example: population census Example: selection of

coach.

Advantages of Sample survey.

Sampling has some advantages over thecomplete count. These are:

As in sample study few units are to be examined

detailed study of the survey can be done. As few units are to be examined the survey work

requires less time. Thus in this way sample surveysaves time.

As few units are to be examined the survey workrequires less money. Thus in this way sample surveysaves lots of money.

In sample survey few persons are required for thesurvey work so experts can be appointed for thesurvey. This will increase the reliability of the surveyresults.

When the test is of destructive nature, sampling isonly the way out. In such cases the population surveyis not possible.

A large area can be covered under survey in theavailable time and money.

If proper method is employed under the survey theresults obtained will represent the populationadequately. Surveys are relatively inexpensive(especially self-administered surveys).


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Surveys are useful in describing the characteristics ofa large population. No other method of observationcan provide this general capability.

They can be administered from remote locations

using mail, email or telephone. Consequently, very large samples are feasible,

making the results statistically significant even whenanalyzing multiple variables.

Many questions can be asked about a given topicgiving considerable flexibility to the analysis.

Sample survey make measurement more precise byenforcing uniform definitions upon the participants.

Sample survey that similar data can be collected fromgroups then interpreted comparatively (between-group study).

Sample survey is also used to check the accuracy ofthe census data (population survey).

Surveys are an efficient way of collecting informationfrom a large number of respondents. Very largesamplings are possible. Statistical techniques can be

used to determine validity, reliability, and statisticalsignificance. Surveys are flexible in the sense that a wide range of

information can be collected. They can be used tostudy attitudes, values, beliefs, and past behaviors.

Because they are standardized, they are relativelyfree from several types of errors.

They are relatively easy to administer. There is an economy in data collection due to the

focus provided by standardized questions. Onlyquestions of interest to the re searcher are asked,recorded, codified, and analyzed. Time and money isnot spent on tangential questions.

Sample surveys are usually cheaper to conduct than afull census.


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Disadvantages of Sample survey.

They depend on subjects motivation, honesty,memory, and ability to respond. Subjects may not be

aware of their reasons for any given action. They mayhave forgotten their reasons. They may not bemotivated to give accurate answers; in fact, they maybe motivated to give answers that present themselvesin a favourable light. Structured surveys, particularly those with closedended questions, may have low validity whenresearching affective variables.

Although the individuals chosen to participate insurveys are often randomly sampled, errors due tononresponsive may exist. That is, people who chooseto respond on the survey may be different from thosewho do not respond, thus biasing the estimates. Forexample, polls or surveys that are conducted by callinga random sample of publicly available telephonenumbers will not include the responses of people withunlisted telephone numbers, mobile (cell) phonenumbers, people who are unable to answer the phone(e.g., because they normally sleep during the time ofday the survey is conducted, because they are at work,etc.), people who do not answer calls from unknown orunfamiliar telephone numbers. Such a survey will include a disproportionatenumber of respondents who have traditional, land-linetelephone service with listed phone numbers, and

people who stay home much of the day and are muchmore likely to be available to participate in the survey(e.g., people who are unemployed, disabled, elderly,etc.). Survey question answer-choices could lead tovague data sets because at times they are relative
http://en.wikipedia.org/wiki/Closed_ended_questionhttp://en.wikipedia.org/wiki/Closed_ended_questionhttp://en.wikipedia.org/wiki/Validity_(psychometric)http://en.wikipedia.org/wiki/Closed_ended_questionhttp://en.wikipedia.org/wiki/Closed_ended_questionhttp://en.wikipedia.org/wiki/Validity_(psychometric)


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only to a personal abstract notion concerning "strengthof choice".

For instance the choice "moderately agree" maymean different things to different subjects, and to

anyone interpreting the data for correlation.

Qualitative data & Quantitative data.

In order to understand a statistical study of aproblem covering different aspects, we have to planan inquiry. Such an inquiry involves inspection of all

the units of population or units of the sample of size nappropriately selected from the population understudy covering different aspects of the problem.Collection of all the results so obtained byinspection of all units of population or itssample is called data. Thus, statistical study of theproblem can be made on the basis of the datacollected either by population inquiry or sample

inquiry. Hence collection of the data forms the basisof the statistical study of any problem.

Suppose we have to study some characteristicassociated with the unit of a sample of size nappropriately selected from population of size N underthe field of inquiry. Since the measurement of thischaracteristic varies from unit to unit in the sample.We call this characteristic as variable characteristic.Variable characteristic of a unit can be eitherqualitative or numerical (quantitative).Weconsider an example to grasp the idea of qualitativeor numerical (quantitative) variable characteristic.


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In sample of size (1nN) of workersappropriately selected from a population of workers ofsize N, worker will be a unit of sample. If to sufferfrom tuberculoses is a variable characteristic

associated with a unit of a sample, then this variablecharacteristic is qualitative and hence thischaracteristic is called qualitative variable. Fromnow onwards, we shall call a qualitative characteristicas an attribute. The collection of observationobtained by inspecting all units of the sample withrespect to this attribute (to suffer from tuberculoses)is called qualitative data. Similarly, if we associate

attributes like to be in debt, to smoke, to drink,to use social network etc, with the units (i.e.workers) of the sample we get a qualitative data onthese attributes.

Suppose we associate a variable characteristicnamely, monthly income of a worker, persons usingsocial network etc. We can get a measurement ofmonthly income of a worker (unit) of the sample.

Since a measurement of this variable characteristic isa non-negative real number we call this variablecharacteristic as a numerical (quantitative)variable. The collection of observation ormeasurements of monthly income of all units(workers) of the sample is numerical data. Similarlywe can associate numerical variables like weight,height, blood pressure, width etc, with units (workers)

of the sample of n workers.Thus we can define this data as follows:

The collection of observation onattributes or measurement on a variablecharacteristic defined on the units of a


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population or a sample selected from it is calleddata. If a variable characteristic is an attribute(qualitative variable), then the collection ofobservation on attribute (qualitative variable) is

called qualitative data. If variable characteristicis a numerical variable the collection ofobservation on the numerical variable is calledNumerical (Quantitative) data.

When the data are collected according tosome qualitative measures which are notcapable of quantitative measurement likebeauty, honesty, employment, intelligence,

occupation, literacy, sex, etc., the data is calledQualitative or Descriptive data. If the data arecollected on the basis of a phenomenon which iscapable of quantitative measurement like age,height, weight, production, incomes, prices,sales, profits, expenditures, incomes, money,etc., are termed as a Quantitative or numericaldata.

Primary data & Secondary data.

It is now known that for a statistical study of anyproblem the information is required to be collected. Thereliability of the results will obviously depend upon theaccuracy of the collected data. If somebody is interestedin studying the progress of the industry, he should collectinformation about the total investment in the industry, the

number of workers, the volume of production, sale, profitetc. there two methods of collecting such data: (1)Primary data (2) Secondary data.

Primary data.


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Primary data are those statistical data which arecollected for the first time or original to the nature.Primary data are originally by the authorities who arerequired to collect them. The source from which primary

data are collected is called primary source. The methodof collection of primary data is also known as the primarymethod of collection of data. Primary data arecollected for the first time by the authority that requiresthe data for their use and treatment. Data collected by thefield-workers, investigators, and enumerators are primarydata. The census of India published by the government,the reserve bank of India bulletin published by the reserve

bank of India, the textile bulletin published by the textilecommissioner of India, annual report of the companyprepared by the company, etc. are the sources of theprimary data.

For example the data collected from the populationcensus held by the government of India every ten yearsare also called primary data. The data collected by theteacher with the help of his students by socio economic

survey for the first time is called primary data. The annualreport presented by the company for the first time for theinvestors is also called the primary data. In case of strikein a nationalized bank if a person approaches differentbank workers and gathers information regarding thecauses of strike and understand the problem of the bankworkers is also called a Primary data

In short Primary data means when anyauthorized organization or an investigators or anenumerators collects the data for the first timehimself or with the help of an institution or anexpert then the data collected. Thus primary data isthe first handed information collected by theinvestigator himself.


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Secondary data.

Secondary data are those statistical datawhich are collected and published by one

organization and subsequently utilized by otherorganizations. Secondary data are originally collectedand published by other organization other than theauthorities who require them subsequently for their useand treatment. So Secondary data of oneorganization becomes primary data of otherorganizations who first collect them and publishedthem. The source from which secondary data iscollected is called Secondary source. The method ofcollection of secondary data is called secondarymethod of collection of data. Secondary data issystematically arranged and in abridged form. With littlechanges in primary data it is useful for the study of thedata. This saves time money and energy.

The Secondary data can be collected from followingsources:

Government publication, Publication of SemiGovernment agencies, Publication of internationalorganization, publication local bodies, Publication ofbusiness and commercial organization, newspapers andmagazines, Publication of private organization, reportspublished by various commission, unpublished sources,etc.

For example I any private body made use of thedata of the population census complied by the authorizedorganization of the government of India, then the complieddata of the population census become secondary data forthe private organization. Similarly if the data obtainedfrom socio-economic survey conducted by the teacher is


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used by some other institution or persons then the data ofthe socio-economic survey becomes secondary for theuser initiation.

Thus in short Secondary data means When anauthorised organization agency or investigator uses thedata already collected by the authorised organizationagency or investigator.

Diff. between Primary & Secondary data.

The difference between the primary data andsecondary data is only one of the degrees of detachmentwith the original source. The data which is primary in thehands of one may become secondary in the hands ofothers. The difference between them can be shown asfollows:

Primary Data Secondary data

Primary data are collectedthe first time. So they areoriginal.

Secondary data arealready collected. So theyare not original.

Primary data are extensiveand in haphazard manner.

Secondary data aresystematic and inabridged form.

In collecting primary datamore time, money, andenergy are used

In collecting secondarydata less time, money,and energy are used.

They are relevant to theinquiry.

They may not be relevantto the inquiry.

In primary data collectionRepresentative is notselected.

In secondary datacollection Representativeis selected.


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1.Direct Inquiry.

2.Indirect Inquiry.

3.Questionnaire Inquiry.

a) By post.

b) By Enumerators.

Direct Inquiry.

A method in which an investigator himself or anenumerators appointed by the institution who wants tocollect personally visits the persons from whom the

information is to be obtained asks them questionpertaining to the inquiry or survey and collect the data orrequired information regarding the survey or inquiry iscalled method of direct inquiry.

For example, suppose a teacher wants to knowwhether students visiting library of the school either theyread the books or newspapers or periodicals or magazines.He visits the library and meets the students personally andasks some questions related to their habits and record theanswer given by them. Thus teacher gathers theinformation from the student and studies what the studentread in the library. The method adopted by the teacher fortheir inquiry is an example of direct inquiry. If a sociologistis interested in studying the causes of the divorce amongthe educated couples, he selects certain couples atrandom and approaches them personally. He gathers the

information from them regarding their problems andstudies the causes of divorce. The method adopted by thesociologist for their inquiry is an also example of directinquiry. There many examples are there of the directinquiry like population census, etc.


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The direct inquiry can be done in two ways. Theyare (1) by observation (2) by interview. The informationcollected or obtained by direct inquiry is generallyconsidered to be reliable. But errors are likely to creep in,

in the information or data collected by the direct inquirymethod on the account of the prejudice or bias of theinvestigator or collector or enumerators. For example, ifthe teacher making an inquiry about the reading habits ofthe students going to library starts his inquiry by theprejudice or bias that students visiting the library mostlyread the books or turn the page of the pictorial newspaperor periodicals then the information collected by the

teacher will create a different impression and cease to bereliable. Thus it requires more time money and energy.

The method of the direct inquiry involves lot oftime money and energy. The method of direct inquiry isadopted when the field of inquiry is limited and inquiryrequires a high standard of the accuracy of the collectedinformation. The success of direct inquiry will naturallydependent upon the skill of the investigator or collector or

enumerators and the co-operation of the respondents orpeople under this inquiry.

This method requires much from the investigatorssuch as:

1. She/he should be polite, unbiased and tactful.

2. She/he should know the local conditions,

customs and traditions.3.She/he should be intelligent and possessing

good observation power.

4. She/he should use simple, easy andmeaningful questions to extract information.


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There are some merits (advantages) and demerits(disadvantages) of the direct inquiry. They are as follows:

Advantages of Direct Inquiry.

Since the investigator or collector or enumeratorshimself collect the data or information by personalvisit the data or information obtained by this methodare accurate and reliable.

The presence of an enumerator or investigatorpossibly creates confidence in the respondents of theinquiry. If the person having doubt or any question or

any embarrassment, he can seek clarification frominvestigator or enumerators.

Investigator or enumerators can become clearer andopen with the matters relating to the inquiry bydeveloping close contact with the person givinginformation and providing more explanation to himrelevant with the inquiry.

The enumerators can indirectly get the informationcase the informant (person giving the information)dodging or is unwilling to give information on somematters. In order to extract information, he can asksome supplementary question consistent with thelevel of the informant. He also assures him thatinformation given to him by him will not be misused.

This method is much better than the information is to

be obtained from a limited field of inquiry.

Usually the investigators or enumerators are familiarwith the local problems; hence their experience canbe useful.


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Due to personal touch, people tend to co-operatebetter and promptness is achieved.

Disadvantages of Direct Inquiry.

Investigator or enumerators cannot visit more placesat a time. Hence this method is not quite useful ingetting more information. It requires more time andmoney to collect the information. Hence this methodrequires considerable amount of time, money andenergy.

Sometimes information collected by this method is

less reliable if the enumerators are not well trained,dutiful, and honest towards the object of the inquiry.

This method is likely to be affected to a large extentby the prejudices or bias of the enumerators.

The respondents may not have interest in the surveyhence it is likely that they may not be co-operative.

The reliability of the result, therefore suffers.

Indirect Inquiry.

When there is not enough time to personally visitthe informants covered under the field of the inquiry orwhen direct inquiry or when direct inquiry becomesprohibitive with respect to time, energy and cost or in thecase the nature of the information to be obtained iscomplex, the investigator gets in touch with an

organisation or an agency the relevant observationthrough that organisation or agency. Thus a method ofinquiry in which the information is obtained with the helpof an organisation or agency instead of enumerators iscalled the method of the indirect inquiry. This method


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The method is also used in different commissionappointed by the government. The person or agency fromwhom the information is obtained is known as witness andthe success of this method depends upon the reliability of

the witness. If the witness is in touch with respondentsand is free from prejudice or bias the information obtainedis reliable. The method is useful in obtaining informationfrom large area at a lower cost and in less time.

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collection of statistical data