General Classification of a Variable

I. Qualitative variable – a variable that yields categorical responses.

Examples: Profession, Economic Status, Ethnicity, etc.

II. Quantitative Variable – a variable that yields numerical responses representing an amount or quantity.

Examples: Income, IQ Scores, Expenditures, Revenues, Etc.

Types of a Quantitative Variable

I. Discrete Quantitative Variable – consists of a

separate, indivisible categories. - no values can exist between two neighboring

categories. - restricted to whole numbers.

- can be obtained through the process of counting.

Examples: Number of Clients, Number of Students Attending Classes, Number of Children, Etc.

II. Continuous Quantitative Variable – there are an infinite number of possible values that fall between any two observed values.- divisible into an infinite number of fractional

parts.- can be obtained through the process of

measurements with corresponding units.

Examples: Amount of time, Blood Pressure, Temperature, Height, Weight, Etc.

Types of Variables According to their Levels of Measurement ( The Scales of Measuring Data)

I. Nominal Scale – consists of a set of categories that have different names, which are mutually exclusive.- it labels and categorize observations, but do not make any quantitative distinctions between observations.

Examples: Sex of a Person Responding to a Questionnaire, Occupation, Professions, Economic Status (Upper, Middle, Low) , Racial Origin, Ethnicity, Type of Life Insurance Owned (Term, Endowment, Straight-Life, Other, None), Automobile Ownership (Yes, No), Etc.

II. Ordinal Scale – consists of a set of categories that are organized in an ordered sequence.- possesses all the properties of the nominal data.- the data are ranked/ordered in a somewhat “bottom to top” or “high to low” scheme.

Examples: 1. Working Performance can be

categorized and ranked as follows:

1 - Best Worker

2 - Second Best Worker

3 – Third Best Worker

and So on

2. Teaching Performance can be categorized and

ordered as follows:

4 – Excellent

3 – Very Satisfactory

2 – Satisfactory

1 – Needs Improvement

3. Faculty Rank can be categorized and ranked as

follows:

Professor

Associate Professor

Assistant Professor

Instructor

4. Restaurant Ratings

Ordered Categories: ***** **** *** ** *

5. Product Satisfaction

Ranked Categories:

Very Unsatisfied

Fairly Unsatisfied

Neutral

Fairly Satisfied

Very Satisfied

6. Standard &Poor’s Bond Ratings

Ordered Categories:

AAA AA A BBB BB B CCC CC C

III. Interval Scale – consists of an ordered set of categories (like an ordinal scale) with the additional requirement that the categories form a series of intervals that are all exactly the same size.

- the distances between any two numbers are known.

- numeric in nature and does not have a stable starting

point or absolute zero.

Examples: Fahrenheit, Celsius (Centigrade), IQ Scores, Personality Test, Scholastic Achievement Test, Calendar Time (Gregorian, Hebrew, or Islamic), Etc..

IV. Ratio Scale – an interval scale with the additional feature of an absolute zero point.

- ratios of numbers do reflect ratios of magnitude.

Examples: Age, Salary, Revenues, Weight, Height, Blood Pressure, Exam Scores, GPA, Expenditures, Etc..

The Role of Statistics in Research

Statistics play a vital role in research. Practically, no research can be complete without statistics. Even in anthropological studies, the use of statistics though minimal is unavoidable.

Some of the Uses of Statistics in Research

1. Statistics helps the researcher in making his research design.

2. Statistical techniques help the researcher in determining the validity and reliability of his research instruments.

3. Statistical manipulations organize raw data systematically to make them appropriate for study.

4. Statistical treatments give meaning and interpretation to raw data and hence, are used to test the hypotheses.

5. Statistical methods determine the levels of significance of the research findings.

Remark: All the facts stated above make statistics a very essential part of research.

Classification of Data

Data may be classified according to source as follows:

I. Primary Data – are those gathered from primary or original sources and direct or first – hand experiences.

The Primary Sources of data are as follows:

1. Individual persons, people of all walks of life.

2. Organized groups such as associations, civic organizations, fraternities, school, business firms, church, armed forces, government offices, lawmaking bodies, families, clans, tribes, courts, etc.

3. Established practices and systems such as marriage ceremonies, religious rites, legal systems, economic systems, customs and traditions, superstitious beliefs, folkways, folk songs, and the like.

4. Documents in their original form such as the constitution, laws, court records, proclamations, treaties, contracts, census, memoirs, autobiographies, letters, diaries, yearbooks and annuals, and all other kinds of original records.

5. Nonhuman living organisms such as animals fowls, insects, and the lower forms of living organisms.

6. Man made material things such as buildings, machines, weapons, appliances, roads and bridges, airplanes, ships, dams, radio, television, telephone, chemicals, and the like.

7. Natural objects and phenomena such as typhoon,

earthquakes, mountain, heavenly bodies, wind, volcanoes,

etc.

II. Secondary Data – are those gathered from secondary

sources. The following are the secondary sources of data:

1. Books including dictionaries, encyclopedias, almanacs,

etc.

2. Articles published in journals, magazines, newspapers, and

other publications.

3. Unpublished theses and dissertations.

3. Monographs, manuscripts, etc.

4. All other second hand sources among which are hearsays,

rumors, etc.

Advantages of Primary Data over Secondary Data

1. The primary data frequently give detailed definitions of

terms and statistical units used in the survey.

2. The secondary data have usually little or no explanatory notes and may contain clerical and typographical mistakes which often arise from transcription of the figures from the original or primary source.

3. The primary data usually include a copy of the schedule and a description of the procedure used in the selection of the type of sample and in collecting the data. This gives the user an idea of accuracy, applicability, and limitation of the survey results.

4. The primary data are usually broken down into finer classifications. The secondary data often omit part of combining categories, such as showing barrios instead of sitios, or municipalities instead of barrios.

Advantages of Secondary Data

1. Secondary data are more convenient to use because they are

already condensed and organized.

2. Analysis and interpretation are done more easily.

3. Libraries make secondary data more easily accessible.

Kinds of Instrument or Tools for Collecting Data

A. Clerical Tools – among the clerical tools or instruments are

as follows:

1. Questionnaire

2. Interview

3. Observation

4. Registration

5. Test

6. Experiment

7. Library

B. Mechanical Tools – include all the tools and equipment used in research in the laboratories in the psychological, medical, chemical, biological, and physical sciences as well as in agriculture, and non-agricultural industries. A few examples are the microscope, telescope, barometer, thermometer, x-ray machine, ultrasound device, stethoscope, burners, scales, and

many others. In the social sciences, the tape recorder, camera, and video tape may be used.

Remark: The choice of the instruments depends upon some factors such as the nature of the research problem, the literacy level of the study population, the cost of the survey, and the time factor.

Characteristic of a Good Research Instrument

1. The instrument must be valid and reliable. An instrument is valid if it gathers accurately data which are intended for it to gather and long enough to be able to gather sufficient information to complete the investigation and to make conclusions.

2. The instrument must be based upon the conceptual framework. The conceptual framework contains the idea or expectation of the researcher of what the result of his investigation should be. The researcher wants to know or find out whether his expectation is true or not.

3. The instrument must gather data that would test the hypotheses or answer the questions or problems under investigation. If a hypothesis has been proved to be true, then it must be accepted otherwise it is rejected. The questions under the Statement of the Problem must be answered by data gathered by the instrument.

4. The instrument must be as objective as possible. It must be free from all sorts of bias. Here is an example of a biased question, “Are you using Colgate? If not, what brand of toothpaste are you using?”. This is a biased question because mentioning Colgate is already a suggestion. To make the question objective or unbiased, it should be “What brand of tooth paste are you using?”

5. The questions should be unequivocal . An equivocal question has two or more interpretations. An unequivocal question has only one interpretation. Here is an example of an equivocal question.” When were you born?” The problem with this question is that it has three possible answers and all are correct: (1) the exact data of birth, (2) month and year of birth,(3) year of birth. Which one should be accepted? To make the question unequivocal if the exact date of birth is desired to be known is “What is your exact date of birth?”

6. The directions to accomplish the instrument must be very clear and definite. The respondents must be told exactly what to do to avoid vagueness of direcions.

7. If the instrument is a mechanical device, it must be of the best brand and the latest design. This is an assurance that the data gathered by the instrument are very accurate and very reliable.

8. The instrument must be accompanied by a good cover letter. The cover letter is a very cordial request for the respondent to accomplish the instrument, mentioning that the research cannot be complete without his response.

9. The instrument must be accompanied by a sponsor’s letter. The sponsor who has some influence upon or over the respondent should request the respondent to help the researcher.

10. The instrument must gather data that are relevant to the problem under investigation. For instance, the problem under investigation is the teaching of social science. The instrument must gather data that deal only with the teaching of social science and not data that deal with the teaching of other subjects.