1. COMMUNICATION ARTS RESEARCH CA3011 A. PARICHART W. AND A. CHULAMANI C.

2. ELEMENTS OF RESEARCH LECTURE 2 PART 2

3. INDEPENDENT AND DEPENDENT VARIABLES

4. INDEPENDENT VS DEPENDENT VARIABLES Independent variables ( ตัวแปรต้น ) are systematically varied by the researcher. Dependent variables ( ตัวแปรตาม ) are observed and their values are presumed to depend on the effects (influence) of the independent variables.

5. EXAMPLE: Determining how the angle of a camera shot affects an audience’s perception of the credibility of a TV news caster Experiment: Three versions of a newscast are recorded: one shot from a very low angle, another from a high angle, and a third from high level. (Independent Variable= the camera angle) (Dependent variable=the the perceived credibility of the newscaster)

6. EXAMPLES To study how marketing mix affect the sales volume To study how brand personality affect the satisfaction level To study how celebrity endorser affect the product trial

7. DISCRETE AND CONTINUOUS VARIABLES A discrete variable includes only a finite set of values; it cannot be divided into subparts. E.g. The member in the family A continuous variable can take on any value including fractions, and can be meaningful broken into smaller subsections. E.g. time spent watching TV (3.13 hours) It does not make sense to say the family size is 2.4

8. LEVEL OF MEASUREMENT

9. THE LEVELS OF THE MEASUREMENT The idea behind measurement is simple: A researcher assigns numerals to objects, event, or properties according to certain rules. Scientists have distinguished four different ways to measure things, or four different levels of measurement-nominal, ordinal, interval, and ratio.

10. THE LEVELS OF THE MEASUREMENT: NOMINAL LEVEL Is the weakest form of measurement. In nominal measurement, numerals of other symbols are used to classify people, objects, or characteristics. It possesses the basic property which is equivalent. Which gender are you? ___ Male ____ Female Which is the medium that you viewed most last week? ___ TV ___ Radio___ Internet ___Magazine ___Newspaper

11. THE LEVELS OF THE MEASUREMENT: ORDINAL LEVEL Objects measured at the ordinal level are usually ranked along some dimension such as from smallest to largest. Ordinal scale possesses the property of equivalence. It also possesses the property of order among the categories. Any given category can be defined as being higher or lower than any other category. Nothing is specified with regard to the distance between any two rankings. What is your socioeconomic? __ lower __ lower middle __middle __ upper middle___ upper What is your education? ___ high school ___Bachelor ___Master ___ Doctoral

12. EXAMPLE : ORDINAL LEVEL Please rank your most favorite television station with 1 and least favorite station with 5. ____ channel 3 ____ channel 5 ____ channel 7 ____ channel 9 ____ channel 11

13. THE LEVELS OF THE MEASUREMENT: INTERVAL LEVEL When a scale has all the properties of an ordinal scale and the intervals between adjacent points on the scale are of equal value Numbers are assigned to the positions of objects on an interval scale in such a way that one may carry out arithmetic operations on the differences between them It lacks a true zero point, or a condition of nothingness. e.g. temperature G.P.A. Zero temperature/no G.P.A. is not possible.

14. THE LEVELS OF THE MEASUREMENT: RATIO LEVEL Ratio level of measurement has all the properties of interval scales plus the existence of a true zero point. e.g. age ( 20 years) time spent watching TV (2 hrs) no. of kids (2 kids) Zero age/time spent is possible.

15. EXAMPLE RATIO How many years have you been working in the newspaper industry? ____ (1 year, 2years…) NOMINAL What is your gender? ___ Male ___ Female Statistics procedures designed for use with higher level of measurement is more powerful than the lower level.

16. MEASUREMENT SCALES

17. A scale represents a composite measure of a variable; it is based on more than one item. Scales are generally used with complex variables that do not easily lend themselves to single-item or single –indicator measurements. Some items, such as age, newspaper circulation, or no. of radios in the house can be adequately measured without scaling techniques.

18. MEASUREMENT SCALES: SIMPLE RATING SCALES Rating scales are used to rate a list of items such as a list of items The researcher’s decision is to decide which type of scale to use: 1to3? 1to 5 1to 7? 1to10?1to 100? Or 0to0 scale. A scale with more points rather than fewer points allows for greater differentiation on the items being rated.

19. EXAMPLE: SIMPLE RATING SCALES e.g. How much do you like the radio program? ___1___2__3__4__5__6__7__8__9__10 How much do you like the jingle? ___1___2__3__4__5__6__7__8__9__10 1-10 scale is universally used in the research

20. MEASUREMENT SCALES: LIKERT SCALES It is also called the summated rating approach. A number of statements are developed with respect to a topic, and respondents can strongly agree, agree, be neutral, disagree, or strongly disagree with the statements.

21. EXAMPLE: LIKERT SCALE ITEMS Only U.S. citizens should be allowed to own broadcasting stations. ___Strongly agree___Agree___Neutral__Disagree___Strongly disagree Prohibiting foreign owner ship of broadcasting stations in bad for business. ___Strongly agree___Agree___Neutral__Disagree___Strongly disagree

22. MEASUREMENT SCALES: SEMANTIC DIFFERENTIAL SCALES This technique is used to measure the meaning an item has for an individual. To use the technique, a name or a concept is placed at the top of a series of seven-point scales anchored by bipolar attitudes.

23. EXAMPLE: SEMANTIC DIFFERENTIAL SCALES Time Magazine (attitude towards Time magazine) Biased ___:___:___:___:___:___:___: Unbiased Trustworthy___:___:___:___:___:___:___:Untrustworthy Valuable ___:___:___:___:___:___:___: Worthless Unfair ___:___:___:___:___:___:___: Fair

24. RELIABILITY AND VALIDITY

25. At least on pilot study should be conducted for any newly developed scale to ensure its reliability and validity. To be useful, a measurement must possess these two related qualities. A measure is reliable if it consistently gives the same answer. If measurements are consistent from one session to another. (today and tomorrow) A measure is valid if it measures what it is supposed to measure. Assessing validity requires some judgments on the part of the researcher.

26. SUMMARY Understanding empirical research requires a basic knowledge of variables and measurement. Independent variables are manipulated by the researcher, whereas dependent variables are what the researcher attempts to explain. Researchers use scales to measure complex variables e.g. Likert, semantic differential scales. Measurement is the assignment of numerals to objects, events. The four levels of measurement are nominal, ordinal, interval, and ratio. To be useful, a measurement must be both reliable and valid. It is crucial for selecting an appropriate the different statistical analyses.

27. HOMEWORK Find a questionnaire used in academic or commercial research. (about 3 pages) Print out and Analyze the level of the measurement of the questions and the type of questions

28. REFERENCE Wimmer, R. & Dominick, J. (2011). Mass Media Research: An Introduction (9 th ed.). Belmont, CA: Thompson Wadsworth.

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