Lecturer Sheet, Chapter – 2 (Collection of Data)

Chapter – 2
Collection of Data

Data : Data is the raw materials of statistical analysis. Data constitute the foundation of statistical analysis and interpretation. Hence the first step in statistical work is to obtain data.

Data are collections of any number of related observations.
Example : We can collect the number of telephones that several workers install on a given day or that one worker installs per day over a period of several days, and we can call the results our data.

Data Set : A collection of data is called a data set.
Data Point : A single observation is called a data point.
Raw Data : Information before it is arranged and analyzed is called raw data.

Needs for data collection :
To realize and analyze the condition of any field it is necessary to collect data. Moreover, we can use these data for deciding our decision about present and future.

Sources of Data :
1. Secondary Source
2. Internal Records
3. Primary Source

1. Secondary Data:
When an investigator uses the data which has already been collected by others, such data are called secondary data.
example: Journals, reports, government publications, publications of research organizations, trade and professional bodies etc.
Secondary data collected from both :
- Published sources and
- Unpublished sources.

Before using secondary data the investigator should examine the following aspects:
a. Whether the data are suitable for the purpose of investigation: The suitability of data can be judged in the light of the nature and scope of investigation.
b. Whether the data are adequate for the purpose of investigation: Adequacy of the data is to be judged in the light of the requirements of the survey and the geographical area covered by the available data. For example, for studying trend of prices we may need data for the last 8-10 years but from the sources known to us may be available for 5-6 years only which would not serve our objective.
c. Whether the data are reliable:




6 W’s for testing reliability of data.
1. Was the collecting agency unbiased?
2. If the enumeration was based on sample or census.
3. Were the data collectors capable and properly trained?
4. Was there a proper check on the accuracy of field work?
5. Was the editing, tabulating and analysis carefully and conscientiously done?
6. What degree of accuracy was desired by the compiler? How far was achieved?

2. Internal data :
Internal data refers to the measurements that are the by-product of routine business record keeping like accounting, finance, production, personnel, quality control, sales, R&D etc.
3. Primary data :
The data collected from original source is primary data. The data obtained by first hand investigation.

Sample: To draw a reasonably accurate conclusions from the study of a small portion of the group called a sample.

Population: A population is a whole, and a sample is a fraction or segment of that whole.
Population means the aggregate of human individuals in a defined area or region.
e.g. All students of this college constitute population.

Methods of obtaining primary data:
1. Questioning: Data are collected by asking questions from people who are thought to have the desired information.
A formal list of questions is called a questionnaire.
Merits/ Advantages of Questioning:
a) Interviewer can help the respondents to understand the questions.
b) The chance of having wrong information is less.
c) The scope of inquiry can be widely spreaded.
d) When the respondents are illiterate even then this method is suitable.
e) Hardly any chance of non-response.
Demerits:
a) This is an expensive method.
b) If the interviewer is not well-trained we may have wrong information.
c) It is largely dependent on the quality of the interviewer.
2. Observation:
Observation is such a method where we have to use eyes rather than ears or voice to collect data.
Advantages:
a) If the respondent is not able enough to provide information or exact information then observation method is suitable.
b) Where there is greater chance of getting wrong information.
c) Useful in natural sciences.
Disadvantages:
a) The scope is very limited.
b) Method is very time consuming.

Consideration for designing a questionnaire:

1. Cover letter
2. The number of questions should be as few as possible.
3. Questions should be logically arranged.
4. Questions should be short and simple.
5. Questions of a sensitive nature should be avoided.
6. Instructions to the respondence.
7. Footnotes
8. Questions should be capable of objective answer.
9. Answer to questions should not require calculations.
10. Pre-testing the questionnaire.
11. Cross-checks.
12. Incentives to respondents.
13. Methods of tabulations to be used.

Pre-testing the Questionnaire:
1. The investigator can find out what are the shortcomings of the questionnaire.
2. An idea can be formed about the extent of non-response likely to take place.
3. Greater co-operation of the informants can be secured.

Editing Primary Data:
1. Editing for completeness.
2. Editing for consistency.
3. Editing for accuracy.
4. Editing for homogeneity.

Differences between Primary Data and Secondary Data.

Primary Data Secondary Data
1. Primary data are collected from the original sources. 1. Secondary data are collected from secondary sources.
2. It is difficult to collect primary data. 2. Secondary data collection is some how easy.
3. To collect primary data is expensive. 3. It is cheap to collect secondary data.
4. Data reliability testing is important for primary data. 4. Secondary data need no such qualification.
5. Primary data are prime. 5. Secondary data are compound.

Assignment-3 (Questionnaire)

NOTICE
Business Statistics - I
Assignment – 3 topics for respective group of BBA 13th Batch students (Section- A, B, C & D). All group required to submit their draft copy of questionnaire before the next class of respective section.
Sl. No. Group Name /
Group Leader Name Section Questionnaire Topic


1. AROK A
Impression of Native people and Foreigner about Bangladesh.
Soptoborno/ Khandakar Zarin Tasnim B
Tushar Hossain C
Md. Shakhawat D

2. Friend’s Chamber A
Flowers marketing in Bangladesh.
Batikrom B
Md. Ariful Alam C
Manojit D

3. NILKONTHO A
Customer choice of retail chain shop (Meena Bazar/Shopnu/Agora).
ALLOUKICK B
Md. Shakur Alam C
4. Dhrobatara/ Md. Jobied Hossain A Customer preference of Online Banking than Traditional Banking.
Apu Bhattacharjee D

5. NIRBHIK B
Readers choice of Books.
Md. Mamunur Rashid C
Sharmin D


6. Shopno Chura A Passenger’s choice of counter bus service than local bus service.
Proloy Shikha B
Asif Ahmed C
Md. Shamim D

7. Zenith / Md. Aynal A
TV viewing habit of people of Dhaka City.

Md. Asif C
Shanaz D
8. Novochary A Consumer preference of soft drinks.
Durunta Pathik B
Volcano C
Assignment Instruction:
- This an group assignment
- Maximum number of questions in the questionnaire is 30 and minimum 20.
- Each group should survey on 30 sample/individual.
- Communicate with me in group if you have any confusion regarding the assignment.