Statistical Data, Source & Types of Data

 

What is Data in Statistics?

Data is a collection of facts, such as numbers, words, measurements, observations etc.

What is Data Collection?

Data collection is a systematic approach to gathering information from a variety of sources to get a complete and accurate picture of an area of interest.  

Source & Types of Data   

 

Primary Data

Primary data are measurements observed and recorded as part of an original study. When the data required for a particular study can be found neither in the internal records or the enterprise nor in published sources, it may become necessary to collect the original data to conduct 1^st hand investigation.

The work of collecting original data is usually limited by time, money & manpower available for the study.


When the data to be collected are very large in volume, it is possible to draw reasonably accurate conclusions from the study of a small portion of the grouped called sample.

Method of Obtaining Primary Data

There are three basic methods of collecting primary data

1. Questioning.
2. Observations.
3. Focused group Discussion (FGD).

Questioning

Questioning, as the name suggests, is distinguished by the fact that data are collected by asking questions from people who are thought to have the desired information.

Questions may be asked in person, or in writing. A formal list of such questions is called a questionnaire.

A distinction is often made between a questionnaire & a schedule. A questionnaire refers to a device for securing answers to questions by using a form which the respondent fills in himself.

Schedule is the name usually applied to a set of questions which are asked & filled in a face-to-face situation with another person.

When the questionnaire method is used, three different techniques of communication with questionnaires are available:

Personal Interview,

Personal interviews are those in which an interviewer obtains information from respondents in face-to-face meetings.

The information obtained by this method is likely to be more accurate because the interviewer can clear up doubts, can cross-examine the informants & thereby obtaining correct information.

E-Mail,

In most mail surveys, questionnaires are mailed to the respondents to fill them & return by mail. Sometimes mail questionnaires are placed in respondents’ hands by other means such as attaching them to consumer products, putting them in magazines or newspapers or having field workers leave them with respondents. In each case, respondents complete the questionnaires themselves & send back the completed forms by mail.

This method has a special advantage in surveys where the field of investigation is very vast & the informants are spread over a wide geographical area.

Telephone,

It is similar to personnel interviews except those communications between interviewer & respondent are by telephone instead of direct personal contact.

However, this method has several limitations such as it cannot be used to interview those people who don't have a telephone, a telephone conversation cannot be very long & also replies on the phone can be erratic & unreliable.

Designing a Questionnaire

While developing a questionnaire, the researcher has to be very clear on the following issues:

• What information will be sought?
• What type(s) of questionnaire will be required?
• How that (those) questionnaire (s) will be administered?
• What the content of the individual question will be?
• What the form of response to each question will be?
• How many questions will be used and how the individual questions will be sequenced?
• Whether the questionnaire shall be disguised or undisguised?
• Whether the questionnaire shall be structured or unstructured?
• Also, while developing a questionnaire, the researcher has to be very clear on the following points
• Should Include Cover Letter
• The Number of Questions should be as few as possible
• Questions should be logically arranged
• Questions Should be Short & Simple
• Questions of sensitive nature should be avoided
• Instructions to the Informants should be there
• There should be footnotes
• Questions should be capable of objective answers
• Answers to questions should not require calculations
• Pre-testing the questionnaire is a must
• Cross Check the Questionnaire
• There should be incentives for respondents
• Method of Tabulation to be used

 

What are the Characteristics of a good Questionnaire?

If a questionnaire is to be used, either as a postal questionnaire or as a basis for interviewing, the following points should be observed in its design.

• The question should be short and simple.
• The question should be unambiguous,
• The best kinds of questions are those which allow a reprinted answer to be ticked.
• The questionnaire should be as short as possible.
• Questions should be neither irrelevant nor too personal.
• Leading questions should not be asked.
• The questionnaire should be designed so that the questions fall into a logical sequence

 
Observations

When the data are collected by observation, the investigator asks no questions. Instead, he observes the object or actions in which he is interested. Sometimes individuals make the observations, on other occasions, mechanical devices observe & record the desired information.

The observation method does not automatically produce accurate data. Physical difficulties in the observation situation on the part of the observer may result in errors. Even more important, however, is the influence on observations of the observer's training, philosophy, opinions & expectations.
Examples are projects such as the reading of X-ray films, ECG, and state of repair for roads.
 

Focused group Discussion (FGD)

When using focused group discussions as a research technique, the researcher is no longer the centre of activity but rather lets informants discuss with each other, providing guidance.

Toolsè Discussion Guide, Tape Recorder

 

From the mentioned methods named above, the questionnaire method is more widely used for collecting business data.

Secondary Data

Before starting a statistical investigation, we must read the existing literature and learn what is already known about the general area in which our specific problem falls.

When an investigator uses the data, which has already been collected by others, such data are called secondary data.

Secondary data can be obtained from journals, reports, government publications, publications of research organizations etc.

The user should be extra cautious in using secondary data & he should not accept it at its face value. The reason is that such data may be full of errors because of bias, adequate size of the sample, arithmetical errors etc.
 
Hence before using secondary data, the investigator should examine the following aspects

• Whether the data are suitable for the purpose of the investigation
• Whether the data are adequate for the purpose of investigation
• Whether the data are viable

 

Internal Data

Internal data refers to the measurements that are the byproduct of routine business record keeping like accounting, finance, production, personnel, quality control, sales, and R&D.

Internal data emerges in the process from payroll, sales amount from a sales journal & the units of finished products produced from production records, cash receipts from cash records.

The chief data source of internal data are the accounting records kept in most business firms.

The problem of collection is primarily that of having the proper record made at the time the information is secured. The information wanted is frequently to be found in more than one department of business, which increases the difficulty of getting just the information one wants.

Internal data when published in any journal becomes secondary data.