Chapter Eight Measurement and Scaling: Fundamentals and Comparative Scaling Copyright © 2010 Pearson Education, Inc. 8-1 Measurement and Scaling Measurement means assigning numbers or other symbols to characteristics of objects according to certain pre-specified rules. • • • One-to-one correspondence between the numbers and the characteristics being measured. The rules for assigning numbers should be standardized and applied uniformly. Rules must not change over objects or time. Copyright © 2010 Pearson Education, Inc. 8-2 Scale Characteristics Description By description, we mean the unique labels or descriptors that are used to designate each value of the scale. All scales possess description. Order By order, we mean the relative sizes or positions of the descriptors. Order is denoted by descriptors such as greater than, less than, and equal to. Copyright © 2010 Pearson Education, Inc. 8-3 Scale Characteristics Distance The characteristic of distance means that absolute differences between the scale descriptors are known and may be expressed in units. Origin The origin characteristic means that the scale has a unique or fixed beginning or true zero point. Copyright © 2010 Pearson Education, Inc. 8-4 Measurement and Scaling Scaling involves creating a continuum upon which measured objects are located. Consider an attitude scale from 1 to 100. Each respondent is assigned a number from 1 to 100, with 1 = Extremely Unfavorable, and 100 = Extremely Favorable. Measurement is the actual assignment of a number from 1 to 100 to each respondent. Scaling is the process of placing the respondents on a continuum with respect to their attitude toward department stores. Copyright © 2010 Pearson Education, Inc. 8-5 Primary Scales of Measurement Copyright © 2010 Pearson Education, Inc. 8-6 Primary Scales of Measurement Copyright © 2010 Pearson Education, Inc. 8-7 Primary Scales of Measurement Scale Fig. 8.1 Nominal Numbers Finish Assigned to Runners Ordinal 7 8 3 Rank Order of Winners Interval Performance Rating on a 0 to 10 Scale Ratio Time to Finish in Seconds Copyright © 2010 Pearson Education, Inc. Finish Third place Second place First place 8.2 9.1 9.6 15.2 14.1 13.4 8-8 Primary Scales of Measurement Copyright © 2010 Pearson Education, Inc. 8-9 Primary Scales of Measurement Nominal Scale • Nominal scale is a naming scale, where variables are simply “named” or labeled, with no specific order as gender, place of residence. • The numbers serve only as labels or tags for identifying and classifying objects. • When used for identification, there is a strict one-to-one correspondence between the numbers and the objects. • The numbers do not reflect the amount of the characteristic possessed by the objects. • The only permissible operation on the numbers in a nominal scale is counting. • Only a limited number of statistics, all of which are based on frequency counts, are permissible, e.g., percentages, and mode. Copyright © 2010 Pearson Education, Inc. 8-10 Primary Scales of Measurement Nominal Scale Example: “Which brand of smartphones do you prefer?” Options : 1- “Apple” 2- “Samsung” 3- “OPPO” In the above example, when a survey respondent selects Apple as their preferred brand, the data entered and associated will be “1”. This helped in quantifying and answering the final question – How many respondents selected Apple, how many selected Samsung, and how many went for OnePlus – and which one is the highest. Copyright © 2010 Pearson Education, Inc. 8-11 Primary Scales of Measurement Ordinal Scale • A ranking scale in which numbers are assigned to objects to indicate the relative extent to which the objects possess some characteristic. • Can determine whether an object has more or less of a characteristic than some other object, but not how much more or less. • Ordinal scale data can be presented in tabular or graphical formats for a researcher to conduct a convenient analysis of collected data. • In addition to the counting operation allowable for nominal scale data, ordinal scales permit the use of statistics based on centiles, e.g., percentile, quartile, median. Copyright © 2010 Pearson Education, Inc. 8-12 Primary Scales of Measurement Ordinal Scale Example: A semantic differential scale question such as: Q- How satisfied are you with our services? 12345- Very Unsatisfied Unsatisfied Neutral Satisfied Very Satisfied This scale not only assigns values to the variables but also measures the rank or order of the variables, such as: • Grades • Satisfaction • Happiness Copyright © 2010 Pearson Education, Inc. 8-13 Primary Scales of Measurement Interval Scale • Interval scale contains all the properties of the ordinal scale, in addition to which, it offers a calculation of the difference between variables. • For instance, consider a Celsius/Fahrenheit temperature scale – • 80 degrees is always higher than 50 degrees and the difference between these two temperatures is the same as the difference between 70 degrees and 40 degrees. • Interval scale is often chosen in research cases where the difference between variables is a mandate – which can’t be achieved using a nominal or ordinal scale. Copyright © 2010 Pearson Education, Inc. 8-14 Primary Scales of Measurement Interval Scale • Example: Q- Please state your annual income 1. 2. 3. 4. 5. Below $40,000 $40,000- $59,999 $60,000- $79,999 $80,000- $99,999 Above $100,000 Copyright © 2010 Pearson Education, Inc. 8-15 Primary Scales of Measurement Ratio Scale • Possesses all the properties of the nominal, ordinal, and interval scales. • It has an absolute zero point. • It is meaningful to compute ratios of scale values. • All statistical techniques can be applied to ratio data. • Because of the existence of true zero value, the ratio scale doesn’t have negative values. Copyright © 2010 Pearson Education, Inc. 8-16 Primary Scales of Measurement Ratio Scale • Example: Q- What is your daughter’s current height? a) b) c) d) Less than 5 feet. 5 feet 1 inch – 5 feet 5 inches 5 feet 6 inches- 6 feet More than 6 feet Q- What is your weight in kilograms? a) b) c) d) e) Less than 50 kilograms 51- 70 kilograms 71- 90 kilograms 91-110 kilograms More than 110 kilograms Copyright © 2010 Pearson Education, Inc. 8-17 Primary Scales of Measurement Table 8.1 Scale Nominal Ordinal Interval Ratio Basic Characteristics Numbers identify & classify objects Common Examples Social Security nos., numbering of football players Nos. indicate the Quality rankings, relative positions rankings of teams of objects but not in a tournament the magnitude of differences between them Differences Temperature between objects (Fahrenheit) Zero point is fixed, Length, weight ratios of scale values can be compared Copyright © 2010 Pearson Education, Inc. Marketing Permissible Statistics Examples Descriptive Inferential Brand nos., store Percentages, Chi-square, types mode binomial test Preference Percentile, rankings, market median position, social class Rank-order correlation, Friedman ANOVA Attitudes, opinions, index Age, sales, income, costs Productmoment Coefficient of variation Range, mean, standard Geometric mean, harmonic mean 8-18 Primary Scales of Measurement Versus Data Type Copyright © 2010 Pearson Education, Inc. 8-19 Copyright © 2010 Pearson Education, Inc. 8-20 Summary – Levels of Measurement Copyright © 2010 Pearson Education, Inc. 8-21