Statistics For Economics Chapter 2 Collection Of Data

(b) Enumerator : The person who go out to the field to collect actual data are called the enumerator.

(c) Respondent : The respondent provide the actual data, by answering the questions in the questionnaire.

1. We will take 10 identical slips. Identical in size, shape and colour to avoid the biased selection.

2. We shall write the name of 10 students on these slips.

3. These slips will be mixed in a bowl.

4. Three slips will be drawn one by one shaking the bowl before every draw.

5. In this way the three students will be selected.

In fact, there is no much difference between the primary and secondary data. Data are primary to an individual or institution collecting them, while they are secondary in the hand of others.

(i) Direct personal investigation.

(ii) Indirect oral investigation.

(iii) Information through mailed questionnaire.

(iv) Questionnaire through enumerators.

1. Published sources :

(а) Government Publications

(b) Semi-government Publications

(c) International Publications

(d) Private Publications

(e) Research Publications
2. Unpublished sources : Secondary Data can be obtained from unpublished sources, because all statistical material is not always published. Studies made by research institutions, scholars etc. can be important sources of secondary data.

Advantages:

(i) The cost of the survey would be smaller.

(ii) The collection of data, their tabulation and analysis would take much less time.

(iii) The magnitude of errors would be much

smaller.

1. Published sources :

(а) Government Publications

(b) Semi-government Publications

(c) International Publications

(d) Private Publications

(e) Research Publications
2. Unpublished sources : Secondary Data can be obtained from unpublished sources, because all statistical material is not always published. Studies made by research institutions, scholars etc. can be important sources of secondary data.

(ii) Sampling method : In this method, few items of the universe are selected and studied on the basis of the sample and then conclusions about the whole universe are drawn.

(ii) Annual Reports of Joint Stock Companies.

(iii) Newspaper such as the Economic Times etc.

(iv) Financial and Economic Journals.

Exclusive series : In this series upper limit of a class becomes the lower limit of the following class.

(b) Every item of the universe has equal chance of getting selected.

(ii) Reports of committees.

(ii) If the universe is large and some units are left out, then it will not be a true sample.

(ii) Indirect investigation

(iii) Information through mailed Questionnaire.

(iv) Questionnaire through enumerators.

(ii) Everyday/once a week/often/once a month.

(iii) Hindustan Times/Novbharat Times/ Indian Express / Dainik Jagran.

(iv) No/Yes/Unjustified/Justified.

(v) Less than 2000/Between 2000-3000/ Between 3000-5000/Between 5000-10000

2. Is increase in electricity charges justified?

3. Do you think smoking should be prohibited ?

4. Do you think wine should be prohibited ?

5. Do you think that small scale industries should be encouraged by the government ?

nearest market.

(ii) Yes, they should be banned because they re not degradable.

(iii) Yes.

(iv) (a) No, (b) Yes, (c) 50 qwintals per hectare.

There is no problem in the above questions.

1. Name of the consumer.............................

2. Sex ........................... Male/Female

3. Permanent address .................................

4. No. of children in the family ...................

5. Do you prefer to eat vegetable Atta Noodles? Yes/No

6. If yes, why do you prefer the particular atta noodles ?

Fair price/Easily available/Good in taste/ Healthier.

7. Do you found the product costly ? Yes/No

8. Do you check the ingredients used ?

Yes/No

It the data are collected and processed by some other agency, they are called secondary data. Generally the published data are secondary data. They can be obtained either from published sources or from any other source. Use of secondary data saves the time and cost.

(i) Personal Interviews : This method is used when the researcher has access to all the members. The investigator conducts face to face interviews with the respondents.

(ii) Mailing Questionnaire : When the data in a survey are collected by mail, the questionnaire is sent to each individual by mail with a request to complete and return it by a given date.

(iii) Telephone Interviews : In a telephone interview the investigator asks questions over the telephone. The advantage of telephone interviews are that they are cheaper than personal interviews and can be conducted in a shorter time. Telephone interview is better in the cases where the respondents are reluctant to answer certain questions in personal interviews.

1. The questionnaire should not be too long. The number of questions should be as minimum as possible.

2. The series of questions should move from general to specific. This helps the respondents feel comfortable.

3. The questions should not be complex. The respondents can answer quickly, correctly and clearly.

4. The questions should not use double negatives. The questions starting with ‘wouldn’t you' or 'don't you' should be avoided.

5. The question should not be a leading question which gives a clue about how the respondent should answer.

6. The question should not indicate alternatives to the answer.

According to the census 2001 population of India is 102.70 crore. It was 23.83 crore according to census 1901. In a period of 100 years, the population of our country increased by 78.87 crores. Census 1991 indicated that the annual growth rate of population during 1980s was 2.14 percent which come down to 1.93 percent during 1990s according to census 2001.

The difference between the actual value of a parameter of the population and its estimate is the sampling error.

Non-sampling errors are more serious than sampling errors because a sampling error can be minimised by taking a larger sample. It is difficult to minimise non-sampling error, even by taking a large sample. This type of error arises from recording of incorrect response.

Non-random Sampling: In a non-random

sampling method all the units of the population do not have an equal chance of being selected and convenience or judgement of the investigator plays an important role in selection of the sample. They are mainly selected on the basis of judgement purpose, convenience or quota and are non-random samples.

Economic facts expressed in terms of numbers are called data. The purpose of data collection is to understand, explain and analyse a problem and causes behind it. Primary data is obtained by conducting a survey. There are other agencies which collect, process, tabulate and publish statistical data. These can be used as secondary data.

1. Preparation of the Questionnaire :

While preparing the questionnaire the

following points should be noted :

(i) The questionnaire should not be very long.

(ii) The questions to be included in the questionnaire must be precise and short.

(iii) The questions should be framed such that they can be cross checked with other questions in the questionnaire.

(iv) The questions should not involve much arithmetical calculations for the enumerator or the respondent.

2. Mode of enquiry : The data may be collected, either by

(i) the interview method, or

(ii) mailing questionnaire.

3. Training of the enumerators: Training programmes for the enumerators have to be arranged, so that they can interpret the questions correctly, explain to the respondents the objectives of the enquiry and importance of the study. They must be trained to be polite in their presentation.

4. Policy survey : In case, it is going to be large scale field study, it is useful to, initially, conduct a survey on a smaller scale (called a pilot survey) before launching the large survey.

Advantages :

1. The enumerator can personally explain to the respondent the objective of the enquiry and importance of the study.

2. This will help in getting better cooperation of the respondent and in obtaining accurate answers to the questions in the questionnaire.

3. The enumerator can help the respondent in interpreting the questions correctly and recording his answers.

4. This will save time of the respondent and will keep him in good humour.

Disadvantages: The method is expensive. We need a large team of enumerators and spend on their training and travel, besides other expenses on food, stationery, lodging etc.

(ii) Mailing questionnaire to respondents:

Advantage : The method of mailing questionnaries to respondents is far more convenient and less expensive.

Disadvantages : (i) The respondents may not understand or misinterpret some questions.

(ii) The respondent may not take enough care to answer all questions correctly.

(iii) The respondent may ignore and not return the questionnaire at all.

(iv) Some of the questionnaires may be lost in the mail.

Data which are not originally collected but rather obtained from published or unpublished sources are known as secondary data.

The difference between primary and secondary data is only of degree. Data which are primary in the hands of one become secondary in the hands of another.

The main sources of error in the collection of data are as follows :

1. Due to direct personal interview.

2. Due to indirect oral interviews.

3. Information from correspondents may be misleading.

4. Mailed questionnaire may not be properly answered.

5. Schedules sent through enumerators, may give wrong information.

1. Purpose of enquiry.

2. Sources of data

3. Methods of data collection

4. Nature and type of enquiry.

5. Unit of collection.

2. The investigator should also see what type of data adequate for the investigation.

3. The investigator must ensure whether the data are reliable to be used.

(i) The status of the agency which collected the data.

(ii) The method used for collecting data.

1. The investigator personally collects the information, the data are original and accurate.

2. The questions can be explained to the informant according to his education standards.

3. Data obtained through this method are more uniform and homogeneous.

Demerits :

1. This method suffers from personal elements and hence conclusions and inferences are likely to be biased.

2. This method of collecting data is very complex.

3. This method involves unnecessary wastage of time and money.

Merits :

1. The merit of this method is that it does not allow the influencing of the respondent by the interviewer.

2. Mailing costs are much lower than the costs of personal visits.

3. It allows the respondents to remain anonymous.

4. It can reach all groups including those whose personal specialization is not possible.

Demerits :

1. This method can be adopted where the informants are literate people.

2. It involves some uncertainty about the

response.

3. The informations supplied by the informants may not be correct.

Example of Population : All the individuals, items, average incomes of people in a certain region, rise in petrol price on the household budget of a particular locality.
Example of variable : Changing prices of foodgrains, Increase / decrease in production of wheat.

Following are the essentials of a good questionnaire :

(i) The questions should be as simple and as clear as possible. The questions should be precise and short so that respondents can provide accurate information.

(ii) The number of questions to be included in questionnaire should not be large since a large number of questions may tire out both the enumerator and respondents.

(iii) The questions should be framed in such a manner that the answers to them are perfectly definite.

(iv) The questionnaire must contain necessary explanations and instructions.

(i) Errors of Measurement: Suppose each student in your class is asked to measure the length of the teacher's table in the class room. Every student is provided a separate measuring tape. If we compare the measurement taken by the students, we will find that the measurements are not identical. The differences in measurements may arise because some students measured upto the nearest of the unit, while others measured to be nearest of the tenth place of decimal. Rounding of errors will always be there.

(ii) Errors due to Mishandling of the Questionnaire : The enumerator, or the respondent may misunderstand, or misinterpret some questions of the questionnaire. Since the scale of operations is large in such survey, large team of enumerators has to be employed. All enumerators may not be equally efficient. Some careless ones may not take their job seriously, even after intensive training. There may also be lack of coordination in the team work.

(iii) Recording Mistakes : The enumerator may commit errors in recording data. For example, he may record 13 instead of 31, and so on. Sometimes the handwriting is so bad and unclear that the tabulator may misread the recorded answers, while transferring data to files or computer.

(iv) Errors of Non-response: These errors arise when the respondent refuses to fill up the questionnaire, or the respondent is not available even after repeated visits of the enumerator. The magnitude of the errors will, generally, be large, if questionnaires are mailed to the respondent and not carried to him personally by the enumerator. The respondent, in that case, may not care, or feel too lazy to return the questionnaire duly filled. In many cases the questionnaires may be lost in the mail.

(v) Arithmetical Errors : If some questions require a little of arithmetical calculations, there is a possibility of such errors. For example, if the question is what was the expenditure on food last month. The head of the household will have to add expenditures on rice, wheat, salt, sugar, milk etc. and also on fruits and vegetables. The errors may occurs in recollecting the items, their prices and adding.

The selection procedure must guarantee this property. The selection procedures are illustrated below :

Suppose there are 40 students in a class, and we are required to select a random sample of 4. We may adopt the following procedure :

(i) Prepare 40 slips of paper of identical shapes and size.

(ii) Write the names of students on the slips (one slip for each student),

(iii) Place the prepared slips in a box and thoroughly mix them.

(iv) Finally, without looking in the box, draw four slips.

(v) The students whose names appear on the slips drawn, constitute the required random sample.

In lotteries, the tickets bought by the people are numbered. They are put in a box and mixed mechanically. Then a required number of tickets are drawn. People holding counterfoils of tickets, bearing the numbers drawn, are the winners. This method is used when the population is homogeneous.

Startified Random Sampling : The method of stratified random sampling requires that:

(i) we subdivide the whole population into a number of homogeneous strata, and

(ii) draw a fixed proportion (say 1% or 1/2% etc.) of individual units from each stratum, by the random sampling method.

This method is used when the population is not homogeneous with regard to the characteristics under investigation. The homogeneity of each stratum, with regard to the characteristics under investigation, is the essential features of this method. The strata may differ significantly from each other.

(1) Census method

(2) Sample method

1. Census Method : Under this method, each and every unit of the universe under survey is studied. For example, if there are 32 students in the class, than the marks of all the 32 students of the class will be collected.

Advantages : This method has following advantages:

1. Results will be absolutely correct, accurate and reliable.

2. There is less possibility of partiality in collecting the data.

3. Extensive knowledge of the problem is possible.

4. Only this method useful, when the units of the universe have different characteristics.

Disadvantages : 1. This method requires a lot of time, energy and money.

2. This method cannot be applied in some

cases.

3. It is an unscientific method.

4. It can be used only in a small universe.

2. Sample Method : Under this method,

data of each, and every unit of the universe is not collected. But data of some representative units of the universe are collected and results may be drawn on the basis of these data for the entire universe.

Advantages : 1. Sample method is easy and scientific.

2. It requires less time and money.

3. This method may be used in those circumstances in which census method may not be used successfully.

Disadvantages : 1. There is possibility of misusing the data.

2. If wrong samples are taken, the analysis will be wrong.

3. This method is applicable only in that universe where various units are similar to each other.

4. The results derived with the help of this method may not be perfectly correct.

The selection procedure must guarantee this property. The selection procedures are illustrated below :

Suppose there are 40 students in a class, and we are required to select a random sample of 4. We may adopt the following procedure :

(i) Prepare 40 slips of paper of identical shapes and size.

(ii) Write the names of students on the slips (one slip for each student),

(iii) Place the prepared slips in a box and thoroughly mix them.

(iv) Finally, without looking in the box, draw four slips.

(v) The students whose names appear on the slips drawn, constitute the required random sample.

In lotteries, the tickets bought by the people are numbered. They are put in a box and mixed mechanically. Then a required number of tickets are drawn. People holding counterfoils of tickets, bearing the numbers drawn, are the winners. This method is used when the population is homogeneous.

Startified Random Sampling : The method of stratified random sampling requires that:

(i) we subdivide the whole population into a number of homogeneous strata, and

(ii) draw a fixed proportion (say 1% or 1/2% etc.) of individual units from each stratum, by the random sampling method.

This method is used when the population is not homogeneous with regard to the characteristics under investigation. The homogeneity of each stratum, with regard to the characteristics under investigation, is the essential features of this method. The strata may differ significantly from each other.

1. Direct Personal Interview : According to this method, data are collected by the investigator personally from persons who are the subject to enquiry. He interviews personally every one who is in a position to supply information he requires. We can use this method of collection of data when area of enquiry is limited or when a maximum degree of accuracy is needed. One can think of personal enquiry in a case of collection of information regarding family budget and living conditions in a group area. The investigator must be skilled, tactful, accurate, pleasing and should not be biased.

2. Indirect Personal Interview : Direct personal enquiry cannot be used in the case of the refusal and reluctance of the persons who are to be interviewed. Then an indirect personal enquiry can be conducted to get a necessary information from an indirect source. Persons who have the knowledge of relevant material are interviewed and asked questions for collecting the data.

3. In this method, local residents or correspondent are appointed in the different parts of the investigation area. These agents regularly supply the information to the central office or investigator. They collect the information according to their own judgements. Radio and newspaper agencies generally obtain information about strikes, thefts, accidents etc. by this method, It is adopted by Government departments to get estimates of agricultural crops and the wholesale price index number. It is suitable when the information is to be obtained from a wide area and where a high degree of accuracy is not required.

4. Mailed questionnaires : A list of questions relating to inquiry, which is called schedule or questionnaire, is prepared. The list of questions provides a space for each answer. Schedules are sent to informants by post, with a request to answer and return it within a specified time. Such schedules generally have prepaid postage stamp affixed to them. If necessary, an assurance is given that the answers will be kept confidential.

5. Questionnaire to be filled by enumerators : Mailed questions method poses a number of difficulties in collection of data. Generally questionnaires received are incomplete, inadequate and unrepresentatives. The second alternative approach is to send trained investigators or enumerators to informants with standardized questionnaire which are to be filled in by the investigators. The investigator help the informations in recording their answers. The investigators should behonest, tactful and painstaking. This is the most common method used by research organisations.

Secondary data may be either (a) Published or (b) Unpublished.

Published Sources :

(i) Government Publications : Different ministers and departments of Central and State

Governments publish regularly current information along with statistical data on a number of subjects. This information is quite reliable for related studies. The examples of such publications are : Annual Survey of Industries, Labour Gazette, Agriculture Statistics of India.

(ii) Publication of International Organization : We can obtain valuable international statistics from official publication of different international organizations, like, The United Nations Organisation (U.N.O.) International Labour Organisation (I.L.O.) International Monetary Fund (I.M.F.) etc.

(iii) Semi-official Publications : Local bodies such as Municipal Corporations, District Boards etc. publish periodical reports which provide factual information about health, sanitation, births, deaths etc.

1. Size : Choice of an appropriate sampling method increases the reliability of data.

2. Sampling errors : Sampling errors reduce the reliability of sample. A sampling error arises due to drawing of inference about the population on the basis of a few observations. There are two types of sampling errors : 1. Biased error, 2. Unbiased error.

3. Non sampling errors : They are more serious than sampling errors because a sampling errors because a sampling error can be minimised by taking a larger sample. It is difficult to minimise non-sampling error, even by taking a large sample. Some of the non-sampling errors are :

(a) Errors in data acquisition

(b) Non response errors

(c) Sampling bias.

Some of the non-sampling errors are :

(i) Errors in data acquisition,

(ii) Non-response erros and

(iii) Sampling bias.

1. This method is very simple.

2. In this method, there is the economy of time, labour and wealth.

3. This method is more feasible in situation of large investigation than the census method.

4. In case of an extensive investigation, this method is more appropriate.

A.

D.

D.

B.

(a) To pay off the debts.

(b) To finance children education

(c) To invest in another property.

(d) To finance your daughter's marriage.

C.

B.

(i) English, (ii) Hindi, (iii) Punjabi, (iv) Urdu.

C.

B.

D.

C.

The selection procedure must guarantee this property. The selection procedures are illustrated below :

Suppose there are 40 students in a class, and we are required to select a random sample of 4. We may adopt the following procedure :

(i) Prepare 40 slips of paper of identical shapes and size.

(ii) Write the names of students on the slips (one slip for each student),

(iii) Place the prepared slips in a box and thoroughly mix them.

(iv) Finally, without looking in the box, draw four slips.

(v) The students whose names appear on the slips drawn, constitute the required random sample.

In lotteries, the tickets bought by the people are numbered. They are put in a box and mixed mechanically. Then a required number of tickets are drawn. People holding counterfoils of tickets, bearing the numbers drawn, are the winners. This method is used when the population is homogeneous.

Startified Random Sampling : The method of stratified random sampling requires that:

(i) we subdivide the whole population into a number of homogeneous strata, and

(ii) draw a fixed proportion (say 1% or 1/2% etc.) of individual units from each stratum, by the random sampling method.

This method is used when the population is not homogeneous with regard to the characteristics under investigation. The homogeneity of each stratum, with regard to the characteristics under investigation, is the essential features of this method. The strata may differ significantly from each other.

1. Reliability of data, 2. Stability of data, and 3. Adequacy of data.

1. A sample is the representative of all the characters of universe.

2. All units of sample must be independent of each other.

3. The number of items in the sample should be fairly adequate.

4. If more than one sample are selected from a universe, these samples should be homogeneous and not contradictory to each other.

(ii) Errors occuring due to communication gap.

(i) Attractive / costly / cheapest / durable.

(ii) Everyday/once a week/often/once a month.

(iii) Hindustan Times/Novbharat Times/ Indian Express / Dainik Jagran.

(iv) No/Yes/Unjustified/Justified.

(v) Less than 2000/Between 2000-3000/ Between 3000-5000/Between 5000-10000

1. Is the electricity supply in your area regular?

2. Is increase in electricity charges justified?

3. Do you think smoking should be prohibited?

4. Do you think wine should be prohibited?

5. Do you think that small scale industries should be encouraged by the government?

(i) I live at two kilometers from the nearest market.

(ii) Yes, they should be banned because they re not degradable.

(iii) Yes.

(iv) (a) No, (b) Yes, (c) 50 qwintals per hectare.

There is no problem in the above questions.

Specimen of questionnaire :

1. Name of the consumer .....................

2. Sex ..................... Male/Female

3. Permanent address .....................

4. No. of children in the family .................

5. Do you prefer to eat vegetable Atta Noodles? Yes/No

6. If yes, why do you prefer the particular atta noodles?

Fair price/Easily available/Good in taste/ Healthier.

7. Do you found the product costly? Yes/No

8. Do you check the ingredients used? Yes/No

Population : All 200 farms Sample : 50 farms.

Examples of Sample : Birth rate, death rate, literacy representative sample of 30 household in order to study the impact of the rise in petrol price on the household budget of a particular locality.

Example of Population : All the individuals, items, average incomes of people in a certain region, rise in petrol price on the household budget of a particular locality.

Example of variable : Changing prices of foodgrains, Increase / decrease in production of wheat.

Choice between the two methods depends upon the objective of the survey. Usually sample surveys are preferred due to following reasons :

1. This method is very simple.

2. In this method, there is the economy of time, labour and wealth.

3. This method is more feasible in situation of large investigation than the census method.

4. In case of an extensive investigation, this method is more appropriate.